'Invalidate' definitions:

Definition of 'invalidate'

From: WordNet
verb
Declare invalid; "The contract was annulled"; "void a plea" [syn: invalidate, annul, quash, void, avoid, nullify] [ant: formalise, formalize, validate]
verb
Make invalid for use; "cancel cheques or tickets" [syn: cancel, invalidate]
verb
Show to be invalid [syn: invalidate, nullify] [ant: validate]
verb
Take away the legal force of or render ineffective; "invalidate a contract" [syn: invalidate, void, vitiate] [ant: validate]

Definition of 'Invalidate'

From: 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]