Opinionist

(n.) One fond of his own notions, or unduly attached to his own opinions.

Thesaurus Entries

Sabbath-breaker, atheist, atheistic, backslider, backsliding, blasphemer, blasphemous, bolter, collaborationist, collaborative, collaborator, convert, defector, degenerate, demurrer, deserter, disloyal, dissenter, dissentient, dissident, faithless, fallen, fallen from grace, fifth columnist, impious, irreligious, irreverent, lapsed, mugwump, nonconformist, objector, opinionist, opposition voice, profanatory, profane, proselyte, protestant, protester, quisling, rat, recidivist, recidivistic, recreant, recusant, renegade, renegado, renegate, reversionist, runagate, sacrilegious, sacrilegist, schismatic, seceder, secessionist, sectarian, sectary, separatist, strikebreaker, tergiversant, tergiversating, tergiversator, traitor, traitorous, treasonable, treasonous, turnabout, turncoat, turntail, unbeliever, undutiful