adjective
vicious, pitiless; causing pain
Synonyms: atrocious, barbarous, bestial, bitter, bloodthirsty, brutal, brutish, callous, cold-blooded, degenerate, demoniac, depraved, evil, excruciating, ferocious, fierce, flinty, hard, hard-hearted, harsh, hateful, heartless, hellish, implacable, inexorable, inhuman, inhumane, malevolent, merciless, monstrous, painful, pernicious, poignant, rancorous, relentless, revengeful, ruthless, sadistic, sinful, spiteful, tyrannical, unfeeling, unkind, unnatural, unrelenting, vengeful, vicious, virulent, wicked
Antonyms: charitable, compassionate, considerate, feeling, gentle, kind, merciful, sympathetic, thoughtful, uncruel