adj. 25B6; adjective RUTHLESS, cruel, harsh, merciless, pitiless, cold-blooded, hard-hearted, callous, brutal, severe, unforgiving, inhumane, inhuman, heartless, unsympathetic, unfeeling.
UNMERCIFUL
Meaning of UNMERCIFUL in English
Concise Oxford thesaurus English vocabulary. Краткий оксфордский словарь английского языка тезаурус. 2012