Another word for dogmatic
Based on an assumption of absolute truth
doctrinal, categorical, canonical, unchangeable, inevitable, immovable, unqualified, eternal, positive, authoritative, systematic, orthodox, formal, ex cathedra, pontifical, imperative, peremptory, theoretical, axiomatic, unerring, by fiat, on faith, as a matter of course, by nature, by God's will, by natural law; see also absolute 1.
Acting as though one possessed absolute truth
dictatorial, doctrinaire, opinionated, arbitrary, overbearing, arrogant, egotistical, bigoted, fanatical, intolerant, imperious, magisterial, domineering, authoritarian, pontifical, positive, peremptory, oracular, tyrannical, fascistic, despotic, obstinate, confident, downright, unequivocal, definite, stubborn, determined, emphatic, insistent, obdurate, closed-minded, narrow-minded, wrongheaded, one-sided, wedded to an opinion, hidebound, high and mighty*, stiff-necked*, hard-shell*, pushy*, pigheaded*, bullheaded*; see also absolute 3, autocratic 1, obstinate.