Source : Webster's Revised Unabridged Dictionary (1913)

Inevitable \In*ev"i*ta*ble\, a. [L. inevitabilis: cf. F.
   in['e]vitable. See {In-} not, and {Evitable}.]
   1. Not evitable; incapable of being shunned; unavoidable;
      certain. ``The inevitable hour.'' --Gray.

            It was inevitable; it was necessary; it was planted
            in the nature of things.              --Burke.

   2. Irresistible. ``Inevitable charms.'' --Dryden.

Source : WordNet®

inevitable
     adj 1: incapable of being avoided or prevented; "the inevitable
            result" [ant: {evitable}]
     2: invariably occurring or appearing; "the inevitable changes
        of the seasons"

inevitable
     n : an unavoidable event; "don't argue with the inevitable"