merciless; relentless; severe; cruel; pitiless.

unsparingly great, extreme, or excessive, as amounts

to talk for an unmerciful length of time.

adjective

generous , kind , merciful , nice

adjective

bestial , bloodthirsty , brutal , coldhearted , hard , heartless , hurtful , implacable , inhumane , merciless , monstrous , pitiless , relentless , remorseless , ruthless , tyrannous , uncaring , unfeeling , unpitying , unrelenting , unsparing , vengeful , vindictive , (colloq.)excessive , cruel , evil , exorbitant , fabulous , harsh , immoderate , inclement , incompassionate , severe , stern , unkind