A person engaged in a political revolution

insurrectionist, revolutionary, revolutionist, agitator, insurgent, insurrectionary, traitor, seditionist, mutineer, subversive, subverter, anarchist, overthrower, nihilist, guerrilla, freedom fighter, member of the uprising, rioter, demagogue, revolter, separatist, malcontent, dissident, schismatic, deserter, dissenter, seceder, apostate, sectarian, turncoat, counterrevolutionary, renegade, secessionist, Sinn Feiner, Trotskyite, underground worker, Third Worlder, refusenik; see also radical.

A person of independent opinions

independent, individualist, iconoclast, nonconformist, maverick, innovator, experimenter, experientialist, malcontent.

To resist or endeavor to overthrow a government or other authority

rise up, rise, resist, revolt, turn against, defy, resist authority, resist lawful authority, fight in the streets, strike, boycott, break with, overturn, mutiny, riot, take up arms against, start an uprising, start a confrontation, secede, renounce, combat, oppose, be insubordinate, be treasonable, upset, overthrow, dethrone, disobey, raise hell*, kick up a row*, run amok*. *

Antonyms submit, obey*, be contented.

To object

dispute, resist, shrink from, be repelled; see oppose 1, recoil.