Webster’s Revised Unabridged Dictionary · 1913
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.