proponent vs protagonist

Other hyponyms of proponent include apologist, justifier, vindicator, commie, communist, constitutionalist, Darwinian, democrat, populist, fascist, federalist, Gnostic, humanist, humanitarian, ideologist, ideologue, internationalist, irredentist, irridentist, isolationist, Jansenist, libertarian, Maoist, Marxist, nationalist, neoclassicist, neutralist, nullifier, drumbeater, partisan, zealot, partitionist, Platonist, pro-lifer, presenter, sponsor, protectionist, republican, ritualist, ruralist, secessionist, secularist, separationist, separatist, interpreter, representative, spokesperson, voice, suffragist, admirer, booster, champion, friend, supporter, supremacist, teleologist, Thatcherite, unilateralist, voice in the wilderness.