Synonyms for Reformist (same or very similar meaning)
WordNet sense 1 (a disputant who advocates reform):
crusader, reformer, meliorist, social reformerWordNet sense 2 (favoring or promoting reform (often by government action)):
progressive, reform-mindedWordNet sense 3 (tolerant of change; not bound by authoritarianism, orthodoxy, or tradition):
liberalFrom the ODE community, based on WordNetadd/edit