Affirmative defense

Affirmative defense is a defense used in litigation between private parties in common law jurisdictions. Such a defense must be plead by a party in order for the court to entertain the defense or it is waived by the party failing to assert it. Generally speaking upon pleading the defense the party has the burden of proof that such defense is a bar to the liability plead by the claimant of the underlying cause of action.

This article is a stub. You can help Wikipedia by fixing it.