The language peculiar to a people or to a district, community, or class
step out of line
to misbehave, to do something offensive or wrong
When the children step out of line their teacher becomes very angry.
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.