adj. 25B6; adjective RUTHLESS, remorseless, pitiless, unforgiving, unsparing, implacable, inexorable, relentless, inflexible, inhumane, inhuman, unsympathetic, unfeeling, intolerant, rigid, severe, cold-blooded, hard-hearted, stony-hearted, heartless, harsh, callous, cruel, brutal, barbarous, cut-throat.
compassionate.