Englishobdurate
adjective
I argued with him but he was obdurate:
stubborn, obstinate, unyielding, unbending, inflexible, intransigent, implacable, pigheaded, bull-headed, mulish, stiff-necked, headstrong, willful, unshakeable, unmalleable, intractable, unpersuadable, unrelenting, relentless, immovable, inexorable, uncompromising, hard, stony, iron, iron-willed, adamant, firm, fixed, determined;
British, informal bloody-minded;
rare indurate.
▷antonyms amenable, compliant, malleable, tractable.