Each is also a cliché.

A simile is a comparison between items with one or more similarities, usually using the words “like” or “as.”

(example, “Love is like a rose.”)

A metaphor is a comparison between two things in which you say that one thing is another.

(example, “Love _is_ a rose.”)

An idiom is an expression that makes sense only if you know what it means – the sort of thing a native speaker grows up with but often gives non-native speakers difficulty. If one looks at the meaning of the phrases, one is likely to be puzzled: what about a button is “cute”?

A cliché is a phrase used so often that it tends to become bland or boring. It is overly predictable, and not creative or original. Again, a native speaker or widely read individual is more likely to recognize an example as cliché because he or she is more likely to have heard it before.

Your question was a bear, but I worked like a dog to figure it out, and I’m happy as a lark about it. 🙂 Have a nice day.

They are also idioms, which means:

1. an expression whose meaning is not predictable from the usual meanings of its constituent elements, as kick the bucket or hang one’s head, or from the general grammatical rules of a language, as the table round for the round table, and that is not a constituent of a larger expression of like characteristics.

2. a language, dialect, or style of speaking peculiar to a people.

3. a construction or expression of one language whose parts correspond to elements in another language but whose total structure or meaning is not matched in the same way in the second language.

A simile is a less vague figure of speech, used when there is a close resemblance between the compared objects.

Idiom means slang terms.