verb

1. To harden; to obdure.

adjective

1. Stubbornly persistent, generally in wrongdoing; refusing to reform or repent.

2. Physically hardened, toughened.

3. Hardened against feeling; hard-hearted.

Synonyms: hard-hearted, hardened, impertinent, intractable, recalcitrant, unrepentant, unyielding