insurgent

(noun) a person who takes part in an armed rebellion against the constituted authority (especially in the hope of improving conditions). Synonyms: insurrectionist, freedom fighter, rebel.

(noun) a member of an irregular armed force that fights a stronger force by sabotage and harassment. Synonyms: guerrilla, guerilla, irregular.

(adj) in opposition to a civil authority or government. Synonyms: seditious, subversive.