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Smell a Rat

Smell a Rat.

English
idiom

Suspect dishonesty or fraud.

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What it means...

To sense that something dishonest or suspicious is happening.

When you smell a rat, your instincts are telling you something isn't right — even if you can't prove it yet.

It's used when a situation or person feels deceptive and you begin to suspect foul play.

Use it when…

  • When a deal or offer seems too good to be true and something feels off
  • When a colleague's behavior suddenly changes and it seems like they're hiding something
  • When the details of a story don't add up and you start to suspect deception

Don’t confuse with...

Wrong icon

"Raise a Red Flag"

To signal that something is potentially problematic or concerning

Wrong icon

"Have a Bad Feeling"

A general sense of unease about a situation, without suspecting deception specifically

Correct icon

"Smell a Rat"

Sensing through instinct that someone is being dishonest or deceptive

Where you’ll hear it

You’ll hear the "Smell a Rat" idiom in real life — at work, in relationships, or in the media.

Work & Business

Corporate Issues

Investors started to smell a rat when the company kept delaying its financial reports quarter after quarter.

Relationships & Social Life

Gossip / Talking About Others

Friends smell a rat when a new acquaintance is suspiciously vague about where all his money comes from.

Media & Everyday Life

TV Shows / Movies

The detective smells a rat when the witness's alibi has too many convenient and perfectly timed details.

Use it like this

Here’s how to use "Smell a Rat" idiom naturally in real conversations, with real examples.

Work & Business

Raising Concerns

You

Something about this contractor feels off — the quote is half the market rate.

Colleague

I smell a rat too — let's check their references carefully before signing anything.

Relationships

Talking to Friend

Friend

He said he was home all night but posted photos from a restaurant.

You

I smell a rat — that doesn't add up at all.

Everyday Conversations

Opinions

Friend

This investment opportunity sounds absolutely perfect — should I go for it?

You

Too perfect — I smell a rat. Let's do some research first.

Last updated:
April 20, 2026

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