THESAURUS
unmerciful
barbarous, bowelless, brutal, brutish, callous, calloused, cold, cold of heart, coldblooded, coldhearted, cruel, dog-eat-dog, flinthearted, flinty, hard, hard of heart, hardened, hardhearted, harsh, heartless, inclement, inexorable, insensitive, mean, merciless, obdurate, pitiless, relentless, remorseless, ruthless, savage, stonyhearted, uncompassionate, uncompassioned, unfeeling, unforgiving, unkind, unnatural, unpitiful, unpitying, unremorseful, unresponsive, unsparing, unsympathetic, unsympathizing, unyielding, vicious, without mercy
ROGET THESAURUS
unmerciful
Pitilessness
N
pitilessness, inclemency, severity, malevolence, pitiless, merciless, ruthless, bowelless, unpitying,
unmerciful, inclement, grim-faced, grim-visaged, incompassionate, uncompassionate, inexorable, harsh, unrelenting.