proponent vs justifier

Other hyponyms of proponent include apologist, 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, protagonist, supporter, supremacist, teleologist, Thatcherite, unilateralist, voice in the wilderness.