invalidate

Verb

Synonyms: annul quash void avoid nullify cancel vitiate

WordNet 3.0

Verb (4)

declare invalid“The contract was annulled”“void a plea”Synonyms: annul quash void avoid nullify
make invalid for use“cancel cheques or tickets”Synonyms: cancel
show to be invalidSynonyms: nullify
take away the legal force of or render ineffective“invalidate a contract”Synonyms: void vitiate

Webster's Dictionary (GCIDE)

Invalidate \In*val"i*date\, v. t. [imp. & p. p. Invalidated; p. pr. & vb. n. Invalidating.] [From Invalid null.] To render invalid; to weaken or lessen the force of; to destroy the authority of; to render of no force or effect; to overthrow; as, to invalidate an agreement or argument. [1913 Webster]