An expression in the usage of a language that is peculiar to itself either in having a meaning that cannot be derived from the conjoined meanings of its elements or in its grammatically atypical use of words.
Idiom:
easy-going
Meaning:
to be tolerant and relaxed
Example:
Our boss has a very easy-going management style.
List of common idioms, their meanings and examples of their usage in sentences
The language peculiar to a people or to a district, community, or class