The Collaborative International Dictionary of English v.0.48:
Insurrectionist \In`sur*rec"tion*ist\, n. One who favors, or takes part in, insurrection; an insurgent. [1913 Webster]WordNet (r) 3.0 (2006):
insurrectionist n 1: a person who takes part in an armed rebellion against the constituted authority (especially in the hope of improving conditions) [syn: insurgent, insurrectionist, freedom fighter, rebel]