سرسخت

bulldog, bullheaded, deep-rooted, defiant, dogged, donkey, fractious, hard-bitten, hard-core, hardened, impervious, implacable, intransigent, invincible, ornery, pertinacious, pigheaded, recalcitrant, refractory, relentless, strong-willed, stubborn, sullen, tough, unregenerate, unyielding, vigorous, wrongheaded