Non Assumpsit Law and Legal Definition

Non Assumpsit is a Latin tern which means he did not undertake. It is an archaic pleading form of a general denial in an action of assumpsit. It is a form of pleading in which the defendant claims that s/he did not undertake or promise any obligation in the manner or form set forth in the plaintiff's complaint.

Under this plea almost every matter may be given in evidence, on the ground that as the action is founded on the contract, and the injury is the nonperformance of it, evidence which disaffirms the obligation of the contract at the time when the action was commenced goes to the gist of the action.