Source : Webster's Revised Unabridged Dictionary (1913)

Inexorable \In*ex"o*ra*ble\, a. [L. inexorabilis: cf. F.
   inexorable. See {In-} not, and {Exorable}, {Adore}.]
   Not to be persuaded or moved by entreaty or prayer; firm;
   determined; unyielding; unchangeable; inflexible; relentless;
   as, an inexorable prince or tyrant; an inexorable judge.
   ``Inexorable equality of laws.'' --Gibbon. ``Death's
   inexorable doom.'' --Dryden.

         You are more inhuman, more inexorable, O, ten times
         more than tigers of Hyrcania.            --Shak.

Source : WordNet®

inexorable
     adj 1: not to be placated or appeased or moved by entreaty; "grim
            determination"; "grim necessity"; "Russia's final
            hour, it seemed, approached with inexorable
            certainty"; "relentless persecution"; "the stern
            demands of parenthood" [syn: {grim}, {relentless}, {stern},
             {unappeasable}, {unforgiving}, {unrelenting}]
     2: not capable of being swayed or diverted from a course;
        unsusceptible to persuasion; "he is adamant in his refusal
        to change his mind"; "Cynthia was inexorable; she would
        have none of him"- W.Churchill; "an intransigent
        conservative opposed to every liberal tendancy" [syn: {adamant},
         {adamantine}, {intransigent}]