Source : Webster's Revised Unabridged Dictionary (1913)

Indisputable \In*dis"pu*ta*ble\ (?; 277), a. [Pref. in- not +
   disputable: cf. F. indisputable.]
   Not disputable; incontrovertible; too evident to admit of
   dispute.

   Syn: Incontestable; unquestionable; incontrovertible;
        undeniable; irrefragable; certain; positive; undoubted;
        sure; infallible. -- {In*dis"pu*ta*ble*ness}, n. --
        {In*dis"pu*ta*bly}, adv.

Source : WordNet®

indisputable
     adj 1: not open to question; obviously true; "undeniable guilt";
            "indisputable evidence of a witness" [syn: {incontestable},
             {undisputable}]
     2: impossible to doubt or dispute; "indisputable (or sure)
        proof" [syn: {sure}]