con·tra·dict / ˌkäntrəˈdikt/ • v. [tr.] deny the truth of (a statement), esp. by asserting the opposite. ∎  assert the opposite of a statement made by (someone). ∎  be in conflict with: that evaporation seems to contradict one of the most fundamental principles of physics.DERIVATIVES: con·tra·dic·tor / -ˈdiktər/ n.

contradict XVI. f. contrādict-, pp. stem of L. contrādīcere, orig. contrā dīcere speak against.
So contradiction XIV. — (O)F. — L. contradictory adj. and sb. XIV. — late L. contrādictōrius. See CONTRA-, DICTION.