irrefragable (adj.) Look up irrefragable at Dictionary.com
"that cannot be refuted," literally "incapable of being broken down," 1530s, from French irréfragable (16c.) and directly from Late Latin irrefragabilis, from assimilated form of in- "not, opposite of" (see in- (1)) + Latin refragari "to oppose, contest," from re- "back" (see re-) + frag-, base of frangere "to break" (from PIE root *bhreg- "to break"). Related: irrefragably; irrefragability.