Synonyms of reformers

2 Syllables
rebel, leftist, rioter, ultraist
3 Syllables
pacifist, insurgent, fanatic, firebrand, mutineer, militant, extremist, revolter, freethinker, left-winger, objector, nihilist, anarchist
4 Syllables
avant-garde, progressive, renegade, secessionist, iconoclast, nonconformist, agitator, subversive
5 Syllables
insurrectionist
6 Syllables
revolutionary