Irrefragable \Ir*ref"ra*ga*ble\, a. [F. irr['e]fragable, L. irrefragabilis. See {Refragable}.] Not refragable; not to be gainsaid or denied; not to be refuted or overthrown; unanswerable; incontestable; undeniable; as, an irrefragable argument; irrefragable evidence. -- {Ir*ref"ra*ga*ble*ness}, n. -- {Ir*ref"ra*ga*bly}, adv. Syn: Incontrovertible; unanswerable; indisputable; unquestionable; incontestable; indubitable; undeniable; irrefutable.