Synonyms of unmerciful

1 Syllable
hard
2 Syllables
ruthless, brutal, monstrous, bestial, heartless, hurtful
3 Syllables
ferocious, pitiless, dog-eat-dog, coldhearted, tyrannous, tigerish, unsparing, uncaring, unpitying, merciless, procrustean, relentless, vengeful, bloodthirsty, unfeeling
4 Syllables
remorseless, implacable, unrelenting, iron-fisted, vindictive, unrepenting, inhumane, ironfisted
5 Syllables
unsympathizing, uncharitable
6 Syllables
unapologetic