(n.) A doctrinaire.

Sabbatarian authoritarian balking balky biased bigot borne bulldogged bulletheaded bullheaded case-hardened closed conceited conservative constricted cramped creedbound deaf deaf to reason doctrinaire doctrinarian dogged dogmatic dogmatizing evangelical extravagant extreme extremist fanatic fanatical fundamentalist haggard hardheaded headstrong hidebound hyperorthodox illiberal inordinate insular intolerant irrational jaundiced lily-white literalist literalistic little little-minded mean mean-minded mean-spirited mulish narrow narrow-hearted narrow-minded narrow-souled narrow-spirited nearsighted obstinate one-sided opinionated opinionative opinioned oracular overenthusiastic overreligious overzealous parochial partial peremptory perfervid persevering pertinacious petty pigheaded pontifical positive positivistic precisianist precisianistic prejudiced pronunciative provincial purblind purist puristic puritanical rabid restive self-opinionated self-opinioned self-willed set shortsighted small small-minded staunch stiff-necked straitlaced strict strong-willed strongheaded stubborn stuffy sulky sullen tenacious ultrazealous uncatholic uncharitable uncooperative ungenerous unliberal unreasonable unregenerate wild-eyed wild-looking willful zealotic