What is an idiom? It is an example of figurative language. Idioms are most often phrases whose meaning cannot be determined by the literal definition of the words themselves. For example, the phrase raining cats and dogs does not mean that animals are literally falling from the sky. The actual meaning is that it is raining very hard. The book The Phantom Tollbooth is filled with idioms which the author, Norman Juster, cleverly slips into his story. Do you know what the following idiom really means? Leave a comment with your answer.