compurgation (kŏm'pərgā`shən), in medieval law, a complete defense. A defendant could establish his innocence or nonliability by taking an oath and by getting a required number of persons to swear they believed his oath. Compurgation, also called wager of law, was found in early Germanic law and in English ecclesiastical law until the 17th cent. In common law it was substantially abolished as a defense in felonies by the Constitutions of Clarendon (1164). Compurgation was still permitted in civil actions for debt, however, and vestiges of it survived until its final abolition in 1833. It is doubtful whether compurgation ever existed in America.