- cussed, obdurate, obstinate, unrepentant - stubbornly persistent in wrongdoing
Antonym: regenerate (indirect, via unregenerate)
- flinty, obdurate, stony - showing unfeeling resistance to tender feelings; "the child's misery would move even the most obdurate heart"
Antonyms: softhearted, soft-boiled (indirect, via hardhearted)