Idioms for something impossible are fun phrases where the words together mean something entirely different from their literal definitions. People use them to add color, description, and humor to everyday conversations. In this article, you will learn sixty interesting idioms that describe something that cannot possibly happen.
In this lesson, we’ll look at idioms that mean a task or goal is completely out of reach. Let’s get started and explore some of these helpful expressions.
Idioms for Something Impossible
1. When pigs fly
Meaning: Something that will never happen because it is completely impossible.
For Example: My little brother said he would clean his messy room when pigs fly. / Winning a trophy in soccer without practicing is going to happen when pigs fly.
Other Ways to Say: Never happening / Not in a million years
2. Once in a blue moon
Meaning: An event that happens so rarely it is practically impossible to plan for.
For Example: Seeing a shooting star while walking the dog happens once in a blue moon. / Finding my favorite candy flavor in the store happens once in a blue moon.
Other Ways to Say: Very rarely / Hardly ever
3. Reach for the moon
Meaning: Trying to achieve a goal that is so grand it is nearly impossible.
For Example: Setting a goal to read five hundred books this year is trying to reach for the moon. / He wants to build a spaceship by himself, which feels like trying to reach for the moon.
Other Ways to Say: Unrealistic goal / Impossible dream
4. Catching smoke
Meaning: Trying to hold onto something that has no physical form and vanishes instantly.
For Example: Tracing the source of the rumor was like catching smoke with your hands. / Trying to keep track of every little detail is like catching smoke.
Other Ways to Say: Impossible grasp / Uncatchable thing
5. Barking up the wrong tree
Meaning: Pursuing a completely impossible or mistaken course of action.
For Example: If you think I took your marker, you are barking up the wrong tree. / He accused his cat of hiding his shoes, but he was barking up the wrong tree.
Other Ways to Say: Wrong guess / Mistaken idea
6. Biting off water
Meaning: Trying to accomplish a physical feat that cannot be done.
For Example: Trying to carry all twenty books at once was like biting off water. / Expecting him to finish that massive puzzle in five minutes is like trying to bite off water.
Other Ways to Say: Impossible task / Overloaded effort
7. Boiling the ocean
Meaning: Attempting a task that is so massive it cannot possibly be finished.
For Example: Trying to clean every single classroom in the school in one hour is like boiling the ocean. / Organizing all the library books by color and author at once is boiling the ocean.
Other Ways to Say: Impossible job / Too big a task
8. Catching wind in a net
Meaning: Trying to capture something that slips right through without stopping.
For Example: Trying to trap the floating bubbles with a cardboard box felt like catching wind in a net. / Explaining complex quantum physics to a toddler is like catching wind in a net.
Other Ways to Say: Useless effort / Impossible capture
9. Climbing a glass wall
Meaning: Facing a barrier that offers no grip and makes success impossible.
For Example: Trying to convince the principal to cancel all homework felt like climbing a glass wall. / Scaling that steep ice slope without boots was like climbing a glass wall.
Other Ways to Say: Impossible climb / Slippery barrier
10. Counting your chickens before they hatch
Meaning: Expecting a result before it has any chance of happening.
For Example: Do not celebrate winning the game yet, because you are counting your chickens before they hatch. / Planning what to buy with prize money you have not won is counting your chickens before they hatch.
Other Ways to Say: Premature hope / Unsure outcome
11. Day and night meeting
Meaning: Two things that are so completely different they can never become one.
For Example: Expecting my neat sister and messy brother to agree on chores is like day and night meeting. / Those two different art styles mixing together well is like day and night meeting.
Other Ways to Say: Total opposite / Impossible mix
12. Drawing blood from a stone
Meaning: Trying to get something from a source that has nothing to give.
For Example: Trying to get an extra cookie from my strict grandma was like drawing blood from a stone. / Asking him for help with money when he has none is like drawing blood from a stone.
Other Ways to Say: Impossible extraction / Empty source
13. Eating your cake and having it too
Meaning: Expecting two impossible or contradictory things at the exact same time.
For Example: You cannot eat your cake and have it too by staying up late and waking up early easily. / Wanting to play video games all day while getting top grades is eating your cake and having it too.
Other Ways to Say: Impossible wish / Contradictory demand
14. Finding a needle in a haystack
Meaning: Searching through an enormous pile for one tiny object that is hidden.
For Example: Looking for my small silver earring in the tall grass was like finding a needle in a haystack. / Finding a clean uniform in my messy laundry pile felt like searching for a needle in a haystack.
Other Ways to Say: Impossible search / Hidden object
15. Fish out of water
Meaning: Being in a situation where you completely do not belong or fit.
For Example: I felt like a fish out of water trying to dance at the talent show. / The puppy looked like a fish out of water sitting on top of the piano.
Other Ways to Say: Out of place / Uncomfortable spot
16. Flying without wings
Meaning: Trying to achieve something major without any of the required tools.
For Example: Trying to build a birdhouse without any wood or nails is like flying without wings. / Attempting the hardest math test without studying is like flying without wings.
Other Ways to Say: Missing tools / Impossible leap
17. Getting blood out of a turnip
Meaning: Trying to force results from a situation that has nothing to offer.
For Example: Asking our empty classroom snack bin for extra treats is like getting blood out of a turnip. / Trying to squeeze more juice from a dry lemon is like getting blood out of a turnip.
Other Ways to Say: Impossible squeeze / Empty result
18. Giving someone the moon
Meaning: Promising something so grand and impossible that it cannot be delivered.
For Example: My little brother promised to buy me a castle, which is like giving someone the moon. / Expecting the school to buy every student a new laptop is like asking for the moon.
Other Ways to Say: Impossible promise / Unrealistic gift
19. Hitting your head against a brick wall
Meaning: Repeating an action that produces zero results and only causes frustration.
For Example: Trying to explain the game rules to him was like hitting my head against a brick wall. / Arguing about who dropped the pencil is like hitting your head against a brick wall.
Other Ways to Say: Pointless action / Frustrating effort
20. Keeping water in a sieve basin
Meaning: Trying to hold onto something that immediately leaks out and escapes.
For Example: Trying to remember fifty random numbers without writing them down is like keeping water in a sieve. / Giving him a secret is like trying to keep water in a sieve.
Other Ways to Say: Leaking container / Impossible retention
21. Leaping over the moon
Meaning: An exaggerated way to describe an impossible athletic feat.
For Example: My cat jumped so high it looked like she was leaping over the moon. / Expecting me to jump across the wide stream is like asking me to leap over the moon.
Other Ways to Say: Impossible jump / Grand leap
22. Making bricks without straw
Meaning: Trying to finish a project without any of the necessary supplies.
For Example: Being asked to paint a mural without any paint brushes is making bricks without straw. / Writing an essay without any paper or pencils is making bricks without straw.
Other Ways to Say: Missing supplies / Impossible task
23. Making silk purses out of sow’s ears
Meaning: Trying to turn something low quality into something luxurious and fine.
For Example: Trying to fix my broken plastic toy with tape is like making silk purses out of sow’s ears. / Redecorating this old broken box into a treasure chest is like making a silk purse out of a sow’s ear.
Other Ways to Say: Impossible makeover / Poor upgrade
24. Moving mountains
Meaning: Attempting a task so gigantic it feels completely impossible to accomplish.
For Example: Trying to get our entire school to clean up the park felt like moving mountains. / Organizing all the classroom supplies by myself felt like moving mountains.
Other Ways to Say: Massive task / Huge effort
25. Out of the blue
Meaning: Something happening so unexpectedly it feels like it came from nowhere.
For Example: Winning the art raffle prize came completely out of the blue. / A sudden rainstorm appeared out of the blue during our soccer game.
Other Ways to Say: Unexpectedly / Sudden surprise
26. Parting the Red Sea
Meaning: Performing an impossible miracle to clear a path through trouble.
For Example: Trying to get through the crowded hallway after the bell rings feels like parting the Red Sea. / Clearing a path for our float in the parade felt like parting the Red Sea.
Other Ways to Say: Miracle clearance / Impossible path
27. Putting the cart before the horse
Meaning: Doing things in a backward order that makes success impossible.
For Example: Trying to write the final book report before reading the book puts the cart before the horse. / Buying a trophy before playing the game is putting the cart before the horse.
Other Ways to Say: Backward plan / Wrong order
28. Reaching for the stars
Meaning: Setting a goal that is way beyond what is realistic or possible.
For Example: Wanting to be the first kid to walk on Mars is reaching for the stars. / Setting a goal to score a hundred on every test without studying is reaching for the stars.
Other Ways to Say: Unrealistic ambition / Grand dream
29. Riding two horses at once
Meaning: Trying to do two conflicting things that cannot happen together.
For Example: Trying to play soccer and basketball at the exact same minute is like riding two horses at once. / Participating in two school plays scheduled at the same hour is riding two horses at once.
Other Ways to Say: Conflicting choices / Impossible split
30. Rolling a boulder uphill
Meaning: Working endlessly on a task that resets itself and never finishes.
For Example: Keeping my little brother’s toy room clean feels like rolling a boulder uphill. / Trying to keep my desk organized every single day feels like rolling a boulder uphill.
Other Ways to Say: Endless task / Tiring struggle
31. Running on empty
Meaning: Trying to keep going when all energy is completely gone.
For Example: After staying up late playing video games, I was running on empty during class. / Our car ran out of gas, leaving us running on empty on the highway.
Other Ways to Say: Exhausted / Out of fuel
32. Seeing stars
Meaning: Experiencing an impact or shock that makes your vision blur impossibly.
For Example: I bumped my head on the low locker door and started seeing stars. / The bright flash of the camera made me see stars for a moment.
Other Ways to Say: Dazed / Dizzy flash
33. Shooting at the moon
Meaning: Aiming for an objective that is far beyond reach.
For Example: Asking for a pony for my birthday is like shooting at the moon. / Trying to win the national spelling bee with zero practice is shooting at the moon.
Other Ways to Say: Unrealistic goal / Impossible aim
34. Stealing candy from a baby
Meaning: A task that is so easy it requires zero effort at all.
For Example: Winning the board game against my little sister was like stealing candy from a baby. / Finding my yellow pencil in an empty pencil case was like stealing candy from a baby.
Other Ways to Say: Super easy / Guaranteed win
35. Storm in a teacup
Meaning: Making a massive fuss over something small and impossible to care about.
For Example: Crying because we ran out of blue markers was a storm in a teacup. / Getting upset over a tiny smudge on your paper is a storm in a teacup.
Other Ways to Say: Overreaction / Silly fuss
36. Swimming against the tide
Meaning: Trying to make progress when every single force opposes you.
For Example: Trying to convince the class to choose math over recess is like swimming against the tide. / Pushing through the crowded hallway against everyone walking is swimming against the tide.
Other Ways to Say: Hard resistance / Going backwards
37. Teaching a fish to fly
Meaning: Attempting to teach a skill to someone or something that cannot possibly learn it.
For Example: Trying to get my pet turtle to fetch a ball is like teaching a fish to fly. / Asking our classroom hamster to solve a crossword puzzle is like teaching a fish to fly.
Other Ways to Say: Impossible lesson / Silly training
38. Telling it to the wall
Meaning: Speaking to someone who refuses to listen or respond at all.
For Example: Arguing with my stubborn little brother is like telling it to the wall. / Asking him to clean up his toys when he ignores you is like telling it to the wall.
Other Ways to Say: Speaking to silence / Ignored advice
39. Turning water into wine
Meaning: Performing an impossible magical transformation of materials.
For Example: Expecting me to turn my old sneakers into brand new shoes is like turning water into wine. / Transforming our messy science project into a masterpiece in one minute is like turning water into wine.
Other Ways to Say: Magic trick / Impossible change
40. Walking on water
Meaning: Pretending or expecting to do something miraculous and impossible.
For Example: My older brother thinks he can score a goal from across the field like he is walking on water. / Expecting me to finish all my homework in five minutes is asking me to walk on water.
Other Ways to Say: Miraculous feat / Impossible act
41. Washing a black dog white cleanser
Meaning: Trying to change something fundamental that cannot be altered.
For Example: Trying to make my cat love taking baths in water is like washing a black dog white. / Trying to change how my sibling tells silly jokes is like washing a black dog white.
Other Ways to Say: Impossible change / Futile effort
42. Wearing two hats
Meaning: Trying to handle two completely different jobs at the exact same time.
For Example: Playing goalie and refereeing the soccer game at once means wearing two hats. / Being the team captain and the equipment manager means wearing two hats.
Other Ways to Say: Dual roles / Juggling tasks
43. Weighing an elephant with a feather
Meaning: Using a tool that is far too small for an impossible task.
For Example: Trying to measure the weight of our heavy backpack with a tiny paper ruler is like weighing an elephant with a feather. / Using a short ruler to measure the whole playground is like weighing an elephant with a feather.
Other Ways to Say: Wrong tool / Impossible measure
44. Whistling in the wind
Meaning: Making a sound or effort that gets lost and accomplishes nothing.
For Example: Complaining about the school rules to an empty room is like whistling in the wind. / Offering advice that nobody listens to is just whistling in the wind.
Other Ways to Say: Ignored effort / Pointless voice
45. Wind in your face
Meaning: Experiencing constant opposition that makes progress nearly impossible.
For Example: Riding my bicycle uphill with a heavy storm wind in my face was tough. / Trying to finish our group project when nobody helps feels like having the wind in your face.
Other Ways to Say: Constant resistance / Hard struggle
46. Wolf in sheep’s clothing
Meaning: Someone who looks harmless but acts impossible and tricky.
For Example: That quiet student who hid all the markers was a wolf in sheep’s clothing. / The easy looking puzzle turned out to be a wolf in sheep’s clothing.
Other Ways to Say: Tricky person / Hidden trap
47. World in your hands
Meaning: Having complete control over everything, which is impossible to maintain.
For Example: Winning the game made me feel like I had the world in my hands. / Trying to manage every single school club at once feels like holding the world in your hands.
Other Ways to Say: Total control / Massive responsibility
48. Writing on water
Meaning: Doing work or making plans that vanish instantly without leaving a trace.
For Example: Drawing designs in the steamed glass window is like writing on water because it disappears. / Making promises that change every day is like writing on water.
Other Ways to Say: Temporary work / Fading plan
49. Zero tolerance
Meaning: A strict rule where breaking it has an impossible way out.
For Example: Our school has a zero tolerance policy for running in the hallways. / The teacher has zero tolerance for talking during the test.
Other Ways to Say: Strict rule / No exceptions
50. Catching a falling star
Meaning: Trying to catch something high in the sky that falls too fast.
For Example: Trying to grab the loose papers blowing away in the wind was like catching a falling star. / Winning the grand prize raffle felt like catching a falling star.
Other Ways to Say: Impossible catch / Rare grab
51. Catching moonbeams in a jar
Meaning: Trying to collect light or ideas that have no physical shape.
For Example: Trying to capture the bright colors of the rainbow in a bottle is like catching moonbeams in a jar. / Explaining a dream you had is like trying to catch moonbeams in a jar.
Other Ways to Say: Impossible collection / Catching light
52. Chasing rainbows
Meaning: Pursuing an illusion or a goal that can never be reached.
For Example: Looking for the end of the rainbow in our backyard was just chasing rainbows. / Hoping to win the lottery without buying a ticket is chasing rainbows.
Other Ways to Say: Pointless pursuit / Impossible dream
53. Climbing a mountain of glass
Meaning: Facing a steep, impossible challenge with no footholds.
For Example: Trying to memorize the entire dictionary in one week is like climbing a mountain of glass. / Solving that impossible riddle felt like climbing a mountain of glass.
Other Ways to Say: Impossible hurdle / Slick climb
54. Drawing water with a sieve
Meaning: Doing an action that fails completely because of a bad tool.
For Example: Trying to carry loose sand in a paper bag is like drawing water with a sieve. / Using a broken calculator for your math test is like drawing water with a sieve.
Other Ways to Say: Defective tool / Useless effort
55. Finding hen’s teeth
Meaning: Searching for something that does not exist anywhere in nature.
For Example: Looking for a purple crayon in our box of red ones is like finding hen’s teeth. / Trying to find a working pen with ink in that old desk drawer is like finding hen’s teeth.
Other Ways to Say: Impossible find / Nonexistent item
56. Keeping oil and water apart
Meaning: Trying to separate two things that refuse to mix together.
For Example: Getting my cat and dog to sit quietly side by side is like keeping oil and water apart. / Trying to mix those two conflicting art paints is like keeping oil and water apart.
Other Ways to Say: Impossible separation / Natural split
57. Making a silk purse from a pumpkin
Meaning: An impossible transformation of a plain object into something fancy.
For Example: Trying to turn my old cardboard box into a shiny race car is like making a silk purse from a pumpkin. / Redecorating our plain classroom with no supplies is like making a silk purse from a pumpkin.
Other Ways to Say: Impossible makeover / Poor transformation
58. Squeezing water from a dry sponge
Meaning: Trying to extract results from a place that is completely empty.
For Example: Asking my brother for more funny stories when he is asleep is like squeezing water from a dry sponge. / Trying to get more ink out of that dead marker is like squeezing water from a dry sponge.
Other Ways to Say: Impossible squeeze / Empty effort
59. Trying to empty the sea with a spoon
Meaning: Doing a task so tiny compared to the goal that it is impossible.
For Example: Trying to clean the entire school gym floor with a toothbrush is like trying to empty the sea with a spoon. / Memorizing every book in the library in one day is like trying to empty the sea with a spoon.
Other Ways to Say: Useless tool / Impossible scale
60. Whipping cream with a fork
Meaning: Using an inefficient method to complete an impossible task.
For Example: Trying to cut thick cardboard with plastic safety scissors is like whipping cream with a fork. / Using a tiny spoon to dig a hole in the hard yard dirt is like whipping cream with a fork.
Other Ways to Say: Wrong method / Useless tool
Exercise to Practice
- My little brother said he would clean his messy room when ________.
- Trying to convince the principal to cancel all homework felt like ________.
- Looking for my small silver earring in the tall grass was like ________.
- Expecting me to finish all my homework in five minutes is asking me to ________.
- Trying to clean every single classroom in the school in one hour is like ________.
- Trying to carry all twenty books at once was like ________.
- Finding a clean uniform in my messy laundry pile felt like searching for ________.
- Trying to get an extra cookie from my strict grandma was like ________.
- Wanting to be the first kid to walk on Mars is ________.
- Trying to get our entire school to clean up the park felt like ________.
- Trying to keep my desk organized every single day feels like ________.
- Finding a purple crayon in our box of red ones is like ________.
- Trying to cut thick cardboard with plastic safety scissors is like ________.
- Expecting the school to buy every student a new laptop is like ________.
- Trying to fix my broken plastic toy with tape is like ________.
Answer Key
- pigs fly
- climbing a glass wall
- finding a needle in a haystack
- walking on water
- boiling the ocean
- biting off water
- a needle in a haystack
- drawing blood from a stone
- reaching for the stars
- moving mountains
- rolling a boulder uphill
- finding hen’s teeth
- whipping cream with a fork
- giving someone the moon
- making silk purses out of sow’s ears
Conclusion
Learning these idioms is a fun way to describe impossible situations and funny extremes with your friends and family. Instead of using plain words, you can use these colorful phrases to make your stories more entertaining when something cannot happen.
Try picking one of these expressions today and use it playfully when someone says something will happen when pigs fly. You will see how much fun it is to use creative language in everyday conversations!
