hierophant

a person who actively supports or favors a cause <as an early hierophant of birth control, Margaret Sanger had to face down often vehement opposition> Synonyms advocate, advocator, apostle, backer, booster, champion, expounder, espouser, friend, gospeler (or gospeller), herald, exponent, high priest, paladin, promoter, proponent, protagonist, supporter, true believer, tub-thumper, white knightRelated Words loyalist, partisan (also partizan), stalwart; adherent, cohort, disciple, follower; interpreter; applauder, cheerleader, encourager, fellow travelerNear Antonyms enemy, foe, rival; belittler, critic, faultfinderAntonyms adversary, antagonist, opponent