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.
invalidated adj : deprived of legal force [syn: {nullified}]