Meaning

adjective stubbornly persistent in wrongdoing

adjective showing unfeeling resistance to tender feelings

originFirst attested in the 1450s, in Middle English; inherited from Middle English obdurat(e), borrowed from Latin obdūrātus (“hardened”), perfect passive participle of obdūrō (“to harden”) (see -ate (adjective-forming suffix)), from ob- (“against”) + dūrō (“to harden, render hard”), from dūrus (“hard”). Compare durable, endure.

Etymology from Wiktionary, CC BY-SA 3.0