From Longman Dictionary of Contemporary Englishsmell wrong/fishy/odd etcsmell wrong/fishy/odd etcinformalSEEM to seem dishonest or untrue The whole thing is beginning to smell fishy to me. → smell
Examples from the Corpus
smell wrong/fishy/odd etc• And then you go out with some other woman and she smells wrong.• Why does fish usually smell fishy?• The Adkinsons' neighbors smelled wrong in the air, but pinched their noses closed and kept to themselves.• So, in short, if a fish smells fishy it is an indication that it is going off. 