Idioms
An idiom is a group of words, or in other words, a phrase that has a meaning other than its literal meaning of the words in it.
Idiom:
back up (someone or something) or back (someone or something) up
Meaning:
to support someone or something
Example:
The supervisor made a mistake and his manager refused to back him up.
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