Sometimes, we are unsure about what to believe. We may hear something, but we’re not sure it’s true. This feeling is called doubt. When people feel doubt, they may use special sayings called idioms to talk about it. These idioms help explain when someone doesn’t fully trust something or someone.
Idioms about doubt are part of everyday talking. They make it easier to share how we feel when things seem unclear or confusing. These phrases can sound funny or strange, but they carry real meaning. In this article, we’ll learn many idioms that show what doubt looks like in words. You might hear them at school, on TV, or even at home. Learning these will help you better understand how people speak when they feel unsure. Let’s take a look at some of the most common ones.
Idioms About Doubt
1. Smell something fishy
Meaning: To think something is not right or honest
Example Sentence:
• I smelled something fishy when he said he finished his homework in five minutes.
• Mom smelled something fishy when the cookies disappeared.
Other ways to say: Feel suspicious, something seems wrong
Fun Fact/Origin: Comes from the idea that bad fish has a strong smell, just like lies are hard to hide.
Usage: Use when something seems untrue or sneaky.
2. Raise an eyebrow
Meaning: To show doubt or surprise
Example Sentence:
• The teacher raised an eyebrow when I said my dog ate my report.
• Dad raised an eyebrow when I asked for ice cream before dinner.
Other ways to say: Be doubtful, show disbelief
Fun Fact/Origin: People often lift an eyebrow when they don’t believe something.
Usage: Use when reacting with doubt or shock.
3. Call into question
Meaning: To doubt if something is true or right
Example Sentence:
• The missing homework called his story into question.
• Her odd behavior called the story into question.
Other ways to say: Doubt, be unsure about
Fun Fact/Origin: It means to ask if something is real or honest.
Usage: Use when something doesn’t seem true.
4. On the fence
Meaning: Not sure what to choose or believe
Example Sentence:
• I’m on the fence about joining the soccer team.
• He was on the fence about which book to read.
Other ways to say: Undecided, unsure
Fun Fact/Origin: Comes from sitting on a fence and not picking a side.
Usage: Use when someone can’t decide.
5. Up in the air
Meaning: Not decided or clear yet
Example Sentence:
• Our vacation plans are still up in the air.
• The game is up in the air because of the rain.
Other ways to say: Unclear, undecided
Fun Fact/Origin: Something in the air hasn’t landed, like a plan not set.
Usage: Use when something isn’t sure yet.
6. Shake your head in disbelief
Meaning: To not believe what you hear or see
Example Sentence:
• I shook my head in disbelief when he said he saw a UFO.
• She shook her head in disbelief at the messy room.
Other ways to say: Doubt strongly, can’t believe
Fun Fact/Origin: People shake their heads when they don’t agree or believe.
Usage: Use when something sounds very untrue.
7. Hard to swallow
Meaning: Difficult to believe or accept
Example Sentence:
• His story about flying pigs was hard to swallow.
• It was hard to swallow that she lost her phone again.
Other ways to say: Hard to believe, sounds fake
Fun Fact/Origin: It compares belief to swallowing something hard.
Usage: Use when something seems untrue.
8. Throw doubt on
Meaning: To make people unsure about something
Example Sentence:
• The blurry photo threw doubt on his story.
• That answer threw doubt on the whole test.
Other ways to say: Make people question, cause suspicion
Fun Fact/Origin: To throw doubt means to send doubt onto something.
Usage: Use when something causes others to question.
9. If I had a nickel for every time…
Meaning: You doubt what someone says because it happens a lot
Example Sentence:
• If I had a nickel for every time he said that, I’d be rich.
• If I had a nickel for every time she lost her keys, I’d buy a new bike.
Other ways to say: That happens a lot, not surprising
Fun Fact/Origin: It’s a funny way to say something is too common to trust.
Usage: Use when something is said too often to believe.
10. Pulling my leg
Meaning: Joking or lying
Example Sentence:
• Are you pulling my leg or did you really win a car?
• He said he saw a dinosaur—I knew he was pulling my leg.
Other ways to say: Teasing, joking
Fun Fact/Origin: Comes from an old joke about tripping people.
Usage: Use when someone tells something silly or untrue.
11. Take it with a grain of salt
Meaning: Don’t fully believe it
Example Sentence:
• I take his stories with a grain of salt—they sound too wild.
• She said she got a perfect score, but I took it with a grain of salt.
Other ways to say: Be doubtful, don’t believe everything
Fun Fact/Origin: Long ago, salt was added to medicine to make it easier to take—meaning, don’t accept it fully.
Usage: Use when something might not be true.
12. Sounds fishy
Meaning: Seems untrue or suspicious
Example Sentence:
• That excuse sounds fishy to me.
• His reason for being late sounds fishy.
Other ways to say: Doesn’t sound right, doubtful
Fun Fact/Origin: “Fishy” is often used when something doesn’t feel honest.
Usage: Use when something feels wrong.
13. Seeing is believing
Meaning: You don’t believe something until you see it
Example Sentence:
• He said he can juggle five balls—seeing is believing.
• I won’t believe that story until I see it myself.
Other ways to say: Prove it, show me
Fun Fact/Origin: People trust their eyes more than words.
Usage: Use when needing proof.
14. Looks too good to be true
Meaning: Seems so good that it must be false
Example Sentence:
• That free iPad deal looks too good to be true.
• The ad promised magic results—it looked too good to be true.
Other ways to say: Doesn’t seem real, very doubtful
Fun Fact/Origin: If something sounds perfect, it often has a catch.
Usage: Use when something is suspiciously good.
15. Devil’s advocate
Meaning: To argue the other side to test it
Example Sentence:
• I’ll play devil’s advocate and say maybe she’s right.
• As a devil’s advocate, what if the idea doesn’t work?
Other ways to say: Argue the other side, test the idea
Fun Fact/Origin: Used in old church trials to check all sides.
Usage: Use when someone is not fully agreeing but wants to test a thought.
16. Second thoughts
Meaning: Doubting a decision
Example Sentence:
• I’m having second thoughts about quitting the team.
• She had second thoughts before buying the dress.
Other ways to say: Doubts, unsure now
Fun Fact/Origin: The first thought is the choice; the second is the doubt.
Usage: Use when you start doubting a choice.
17. Don’t bet on it
Meaning: It probably won’t happen
Example Sentence:
• He said he’d clean his room—don’t bet on it.
• She says she’ll be early, but don’t bet on it.
Other ways to say: Not likely, doubtful
Fun Fact/Origin: Comes from gambling—don’t place your money on it.
Usage: Use when something isn’t likely to happen.
18. Question mark hanging over
Meaning: Something is uncertain
Example Sentence:
• There’s a question mark hanging over the game because of rain.
• A question mark hangs over who will win.
Other ways to say: Not sure, unknown
Fun Fact/Origin: The question mark symbol shows doubt or uncertainty.
Usage: Use when something isn’t clear.
19. Something doesn’t add up
Meaning: Something seems wrong
Example Sentence:
• His story doesn’t add up—he was in two places at once.
• The test scores don’t add up with the class work.
Other ways to say: Seems false, not right
Fun Fact/Origin: Like in math, if numbers don’t match, something’s off.
Usage: Use when a story seems incorrect.
20. Give someone the benefit of the doubt
Meaning: Believe someone even if unsure
Example Sentence:
• I’ll give her the benefit of the doubt—maybe she forgot.
• He might be late, but I’ll give him the benefit of the doubt.
Other ways to say: Trust for now, believe kindly
Fun Fact/Origin: It means giving someone a chance even when unsure.
Usage: Use when choosing to believe someone kindly.
21. Hang in the balance
Meaning: Not decided yet
Example Sentence:
• The team’s future hangs in the balance after the big game.
• The results hang in the balance until tomorrow.
Other ways to say: Could go either way, unsure
Fun Fact/Origin: Comes from a scale not tipping either way.
Usage: Use when something is waiting to be decided.
22. Cloud of doubt
Meaning: A strong feeling of doubt
Example Sentence:
• A cloud of doubt followed the team after the loss.
• There’s a cloud of doubt over his story.
Other ways to say: Strong doubt, not trusted
Fun Fact/Origin: A cloud blocks light—like doubt hides the truth.
Usage: Use when doubt is very strong.
23. Don’t hold your breath
Meaning: Don’t expect it to happen soon
Example Sentence:
• He said he’ll clean his room—don’t hold your breath.
• She promised to bring snacks—don’t hold your breath.
Other ways to say: Not likely, doubtful
Fun Fact/Origin: Holding your breath means waiting—this says don’t.
Usage: Use when you don’t expect something.
24. Not buy it
Meaning: Not believe something
Example Sentence:
• He said he saw a ghost, but I didn’t buy it.
• She said the cat ate her homework—I’m not buying it.
Other ways to say: Don’t believe, not convinced
Fun Fact/Origin: “Buy” here means accept an idea as true.
Usage: Use when you doubt a story.
25. Too many holes
Meaning: A story has many problems or doubts
Example Sentence:
• His excuse has too many holes.
• That plan has too many holes to work.
Other ways to say: Doesn’t make sense, not solid
Fun Fact/Origin: Like a bucket with holes—things fall through.
Usage: Use when something is not believable.
26. Looks shady
Meaning: Seems dishonest or suspicious
Example Sentence:
• That email looks shady—don’t click it.
• He gave a shady answer when asked.
Other ways to say: Unclear, suspicious
Fun Fact/Origin: “Shady” means hiding in the shadows.
Usage: Use when something seems sneaky.
27. Give the cold shoulder
Meaning: To ignore or not trust someone
Example Sentence:
• After the fight, she gave him the cold shoulder.
• He gave the cold shoulder when asked about it.
Other ways to say: Ignore, avoid
Fun Fact/Origin: Long ago, giving a cold shoulder of meat was a sign to leave.
Usage: Use when someone acts distant or untrusting.
28. Split decision
Meaning: People can’t agree
Example Sentence:
• It was a split decision about where to eat.
• The vote was a split decision—no clear winner.
Other ways to say: Not agreed, unclear choice
Fun Fact/Origin: Often used in sports when judges don’t agree.
Usage: Use when opinions are divided.
29. Cast doubt on
Meaning: Make something seem less true
Example Sentence:
• The news cast doubt on the story.
• His answer cast doubt on his reason for being late.
Other ways to say: Question, create doubt
Fun Fact/Origin: “Cast” means to throw—so it throws doubt on something.
Usage: Use when new info makes a story less believable.
30. Not convinced
Meaning: Still unsure about something
Example Sentence:
• I’m not convinced he did his homework.
• She said she saw a bear, but I’m not convinced.
Other ways to say: Doubtful, not sure
Fun Fact/Origin: Comes from the idea of needing more proof.
Usage: Use when not fully believing someone.
31. Thin ice
Meaning: In a risky or doubtful situation
Example Sentence:
• He’s on thin ice after missing class again.
• She’s on thin ice with that excuse.
Other ways to say: In danger, at risk
Fun Fact/Origin: Walking on thin ice is dangerous and could break.
Usage: Use when someone is close to getting in trouble.
32. Wavering
Meaning: Unsure or changing back and forth
Example Sentence:
• He kept wavering about which game to buy.
• She was wavering on her decision to quit.
Other ways to say: Can’t decide, going back and forth
Fun Fact/Origin: Comes from the word “wave”—which goes back and forth.
Usage: Use when someone is unsure what to do.
33. Looks sketchy
Meaning: Seems unsafe or suspicious
Example Sentence:
• That place looks sketchy—let’s go somewhere else.
• The story he told sounded sketchy.
Other ways to say: Doubtful, untrustworthy
Fun Fact/Origin: “Sketchy” means rough or unclear, like a quick drawing.
Usage: Use when something feels not safe or not true.
Quiz: Idioms About Doubt
Instructions: Read each question and the answer choices carefully. Pick the letter that best matches the meaning of the phrase or expression.
Question Key
1. What does “smell something fishy” mean?
A) Something smells bad
B) Something feels wrong or untrue
C) You see a fish at the store
2. If someone is “on the fence,” what does that mean?
A) They are sitting high up
B) They are making fun of someone
C) They can’t decide what to do
3. What does “take it with a grain of salt” mean?
A) Add salt to your food
B) Don’t fully believe something
C) Tell a joke
4. When someone says, “That story doesn’t add up,” they mean:
A) It sounds like math
B) It’s hard to believe
C) It’s very clear and true
5. If something is “up in the air,” what does it mean?
A) It’s flying
B) It’s undecided
C) It’s finished
6. What does “pulling my leg” mean?
A) Someone is telling a joke or lie
B) Someone is playing soccer
C) Someone is helping you stand
7. If someone “gives the cold shoulder,” they are:
A) Offering you ice
B) Ignoring or avoiding you
C) Making you laugh
8. When you “give someone the benefit of the doubt,” you:
A) Blame them
B) Believe them even if unsure
C) Prove they are lying
9. What does “too many holes” mean in a story?
A) The story is about donuts
B) The story is confusing or unbelievable
C) The story is very short
10. If something “looks shady,” it probably:
A) Feels safe
B) Is well-lit
C) Seems dishonest or strange
11. When someone says, “Don’t hold your breath,” what do they mean?
A) You will get it soon
B) Don’t wait for it to happen
C) Keep breathing
12. What does it mean when someone is “on thin ice”?
A) They are ice skating
B) They are in a risky situation
C) They are cold
Answer Key
- B – Something feels wrong or untrue
- C – They can’t decide what to do
- B – Don’t fully believe something
- B – It’s hard to believe
- B – It’s undecided
- A – Someone is telling a joke or lie
- B – Ignoring or avoiding you
- B – Believe them even if unsure
- B – The story is confusing or unbelievable
- C – Seems dishonest or strange
- B – Don’t wait for it to happen
- B – They are in a risky situation
Wrapping Up
Doubt can happen to anyone. It helps us think before we believe something. People use idioms to show they are unsure or don’t trust something. These idioms make speaking more fun and help others understand how we feel.
Now that you know 33 idioms about doubt, you can listen for them in conversations. You might even use a few yourself when you feel unsure. They help show when something just doesn’t feel right.
