inexorable in WordNet English dictionary

1. impervious to pleas, persuasion, requests, reason
   "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 tendency"
   adamant  adamantine  inexorable  intransigent 
   
2. 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"
   grim  inexorable  relentless  stern  unappeasable  unforgiving  unrelenting