unforgiving Synonyms

inexorable unrelenting grim unappeasable stern relentless stony severe unmerciful unkind unfeeling spiteful uncompromising uncharitable unbending tough unvindictive unsparing unsympathizing unsympathetic uncompassionate unstoppable inhumane sadistic barbaric unpitying unyielding wreakful vindictive vindicative vengeful ruthless rigid hard-hearted hard forbidding flinty diamantine deadly cruel cold-blooded callous brutal bowelless adamantine harsh heartless implacable revengeful remorseless