In a civil case, a counterclaim is made by the Defendant against the Plaintiff alleging they did something to cause or aggravate the issue.

Merriam-Webster Online Dictionary

counterclaim (noun)

an opposing claim , especially a claim brought by a defendant against a plaintiff in a legal action

counterclaim (verb)

intransitive verb

transitive verb

to enter or plead a counterclaim to ask in a counterclaim

Counterclaim