What does "irrefragable" mean?

Irrefragable: 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.

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