invalidate

v. 使无效力，证明无效

introvert, introverted, intrude, intruder, intrusion, intrusive, intuit, intuition, intuitional, intuitive, intuitively, intumescence, Inuit, inundate, inundation, inure, inured, invade, invader, invalid, invalidism, invalidity, invaluable, invariability, invariable, invariably, invariance, invasion, invasive, invective, inveigh, inveigle, invent, invention, inventive, inventor, inventory, inverse, inversely, inversion,