Idioms
The language peculiar to a people or to a district, community, or class
Idiom:
up to (something)
Meaning:
to be occupied in or planning some activity that is often bad
Example:
I do not know what the boy was up to last night but it was probably something bad.
List of common idioms, their meanings and examples of their usage in sentences
An idiom is a widely used saying or expression containing a figurative meaning that differs from the phrase's literal meaning.