pitiless, remorseless, ruthless, unpitying
Meaning: without mercy or pity; "an act of ruthless ferocity"; "a monster of remorseless cruelty"
There fell one final blow, ruthless as the wrath of God.
To-morrow a ruthless hand will close around your throats.
Pride they consider the most execrable vice, and one who acts proudly is chastised with the most ruthless correction.
So fearful is its portrayal of social disease, so ruthless its stripping of the painted charms from vice, that its tendency cannot but be strongly for good.
Black Donald is the chief of a band of ruthless desperadoes that infest these mountain roads, robbing mail coaches, stealing negroes, breaking into houses and committing every sort of depredation.
Few men exhibit greater diversity, or, if we may so express it, greater antithesis of character, than the native warrior of North America. In war, he is daring, boastful, cunning, ruthless, self-denying, and self-devoted; in peace, just, generous, hospitable, revengeful, superstitious, modest, and commonly chaste.