plea The reply to a plaint ; a mode of defence in an action an law. In a criminal prosecution the prisoner has to plead to the indictment, which he may do (1) by pleading to the jurisdiction, that is, alleging that the court has no jurisdiction to try him; (2) by a demurrer ; or (3) by some plea in bar, either a general plea, guilty, or not guilty, or a special plea, such as autrefois acquit. The accused may plead not guilty in addition to any demurrer of special plea. He may pled not guilty of the offence charged but guilty demurrer or special plea. He may plead not guilty of the offence charged but guilty of another offence of which he might be found guilty on the indictment.