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:
roll up one's sleeves
Meaning:
to prepare to work hard or seriously at something
Example:
Everybody in our club rolled up their sleeves to help prepare for the party.
List of common idioms, their meanings and examples of their usage in sentences
An idiom is a group of words, or in other words, a phrase that has a meaning different from the literal meaning of the words in it.