ruthless

Synonyms: adamant barbarous brutal callous cold cold-blooded cruel cutthroat dog-eat-dog feral ferocious fierce grim hard hard-hearted harsh implacable inexorable inhuman ironfisted killer malevolent merciless mortal obdurate pitiless rancorous relentless remorseless revengeful sadistic savage severe stern stony surly unappeasable unfeeling unforgiving unmerciful unrelenting unsympathetic unyielding vicious vindictive without pity compassionate considerate gentle giving kind nice sympathetic