Idiom

Idiom is an expression, word or phrase that has a figurative meaning that is comprehended in regard to a common use of that expression that is separate from the literal meaning or definition of the words of which it is made.

Example of idioms:

Dark horse: unexpected winner.

Kick the bucket: die.

Keep one's distance: be reserved.

Pull a long face: look serious.

Gain the ear: get favourable hearing.

An old flame: an old passion.