In·val·i·date v. t. [imp. & p. p. Invalidated p. pr. & vb. n. Invalidating.]  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.
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  invalidated
       adj : deprived of legal force [syn: nullified]