سر سخت (صفت)
headstrong, dogged, obstinate, tough, tenacious, vivid, vivacious, stubborn, recalcitrant, hardy, enduring, bull-headed, pigheaded, froward, die-hard, refractory, hard-bitten, hard-fought, incompliant, nine-lived, renitent, self-opinionated, stiff-necked, subsistent
مقاوم (صفت)
resistant, persistent, opposing, insistent, refractory, resisting, renitent