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Idiom of the Day: Smell a Rat

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Have you ever felt that someone is telling you something that is not true? Perhaps they are trying to lie to you. In that case, you smell a rat!

When we feel that something someone or something is not honest, we smell a rat.

"I smell a rat. If John was off from work all week because he was sick, why has he got a suntan?"

"I think my girlfriend is seeing another man. I smell a rat. She told me she went out with Donna last night, but I saw Donna today and she said she hadn't seen my girlfriend this week."

"I started to smell a rat when he said he was working late, but when I drove past his office all the lights were off."

'Man beaten in Cairo now blames protesters – but campaigners smell a rat' (headline from The Independent newspaper (UK) on 3 February, 2013.)

In English we have a similar expression, It smells fishy, which is also used when we feel that something is not right.


To smell a rat is an idiom, the key word to understanding it is the adjective suspicious.

Suspicious: causing a feeling that something is wrong or that someone is behaving wrongly.

"That guy has been standing on the corner of my street for 3 hours. He’s making me suspicious. He acting suspiciously."
"Yeah, I saw him. He looks suspicious."

"The police checked the suspicious van that was parked outside the bank."

The verb form is suspect. When we suspect someone, we think we know the truth about them.

"I suspect he is lying to me. He said he didn’t eat the cake but he had crumbs on his shirt."

Suspicion is the noun form.  It can be used as a countable or uncountable noun depending on context.

Uncountable: when we feel someone is guilty of committing a crime or doing a bad thing:

"She is under suspicion of murder."

"He was arrested on suspicion of theft."

"The police are sure he was not involved. He is above suspicion."

Countable:  a feeling that you know the truth about something.

"Nobody has said who broke my window, but I have my suspicions."

"I have a suspicion he's much younger than he says he is."


When someone has a suspicious character, we can informally describe them as shady. A dishonest person has a shady character.

"Be careful, he seems shady to me."

The American rapper Eminem (real name Marshall Mathers) sometimes uses a character in his songs called, "Slim Shady". The shady part of his him name implies an untrustworthy person.

Now complete these sentences with the correct word:

  • 1 - The first time I ___ a rat was when he said I would treble my money if I invested in his company.

  • 2 - I ___ he was lying to us all the time.

  • 3 - Who's that ___ looking guy standing by the door?

  • 4 - There has always been a ____ that he stole the diamonds.

  • 5 - I can't tell you who I think did it, but I have my ___.