The language peculiar to a people or to a district, community, or class
Idiom:
under cover
Meaning:
hidden, concealed
Example:
The police officer was under cover during the robbery.
List of common idioms, their meanings and examples of their usage in sentences
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.