Counterclaim Definition: A defendant's claim against a plaintiff. A counter document filed by a defendant who, in addition to seeking to defend against a statement of claim, wishes to make his own separate and independent claim against the plaintiff for some cause of action related enough with the statement of claim, or flowing from the facts contained therein, such that it ought to be, and is conveniently joined and heard at the same time as the trial on the statement of claim. It is not just a set-off and is not a defence, although in practice it can act as a factual and tactical buttress against the claim. Categories & Topics: Civil Litigation & Evidence Law Dictionary Find you are constantly looking up definitions? Try our search provider (works in most modern browsers) If you find an error or omission in Duhaime's Legal Dictionary, or if you have legal term suggestion, we'd love to hear from you!