Breadcrumb Home > Dictionary > Index I invalidate: Meaning and Definition of Find definitions for: in•val•i•date Pronunciation: (in-val'i-dāt"), [key] — -dat•ed, -dat•ing. to render invalid; discredit. to deprive of legal force or efficacy; nullify. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: invalidate (Thesaurus) invalid invalidism ✖ Related Content Daily Word Quiz: donnybrook Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language