Verbs

(v)invalidate, annul, quash, void, avoid, nullifydeclare invalid“The contract was annulled”, “void a plea”
(v)cancel, invalidatemake invalid for use“cancel cheques or tickets”
(v)invalidate, nullifyshow to be invalid
(v)invalidate, void, vitiatetake away the legal force of or render ineffective“invalidate a contract”