smell fishy

Idioms and Phrases

Be suspect or suspicious, as in His explanation definitely smells fishy; my guess is that he's lying . This idiom alludes to the fact that fresh fish have no odor but stale or rotten ones do. [Early 1800s]

Example Sentences

But there are several other elements in the alleged plot that smell fishy.

From The Daily Beast

Say, Laurie, course your friends are all right, an' it's none o' my business; but they smell fishy to me a mile off.

From Project Gutenberg