Smell A Rat – English Flashcard for Smell A Rat Updated: July 16, 2019 by Dr. Mohammad Hossein Hariri AslSmell a ratSmell a rat (idiom)to sense that something wrong, unpleasant, dishonest or troublesome is going to happen:John realized that the guests had been whispering vaguely about a blatant incident before he smelled a rat.