Terrorist \Ter"ror*ist\, n. [F. terroriste.]

1. One who governs by terrorism or intimidation; specifically, an agent or partisan of the revolutionary tribunal during the Reign of Terror in France. --Burke. [1913 Webster]

2. One who commits terrorism[2]. [PJC]

Source: The Collaborative International Dictionary of English v.0.48
 

121 Moby Thesaurus words for "terrorist": Bolshevik, Bolshevist, Bolshie, Carbonarist, Carbonaro, Castroist, Castroite, Charley, Communist, Cong, Fenian, Guevarist, Jacobin, Leninist, Mafioso, Maoist, Marxist, Mau-Mau, Puritan, Red, Red Republican, Roundhead, Sinn Feiner, Trotskyist, Trotskyite, VC, Vietcong, Yankee, Yankee Doodle, Young Turk, alarmist, anarch, anarchist, annihilator, arsonist, assassin, beast, beldam, berserk, berserker, biblioclast, bomber, bonnet rouge, brute, burner, criminal, criminal syndicalist, demolisher, demon, desperado, destroyer, devil, dragon, dynamitard, dynamiter, exterminator, felon, fiend, fire-eater, firebrand, fury, goon, gorilla, gunman, gunsel, hardnose, hell-raiser, hellcat, hellhound, hellion, holy terror, hood, hoodlum, hothead, hotspur, hun, iconoclast, idol breaker, idoloclast, incendiary, insurgent, killer, mad dog, madcap, monster, mugger, nihilist, radical, rapist, rebel, red, revolutionary, revolutionary junta, revolutioner, revolutionist, revolutionizer, ruiner, sans-culotte, sans-culottist, savage, scaremonger, she-wolf, spitfire, subversive, syndicalist, termagant, terror, thug, tiger, tigress, tough, tough guy, ugly customer, vandal, violent, virago, vixen, wild beast, witch, wolf, wrecker

Source: Moby Thesaurus II by Grady Ward, 1.0
 

terrorist adj : characteristic of someone who employs terrorism (especially as a political weapon); "terrorist activity"; "terrorist state"

noun

a radical who employs terror as a political weapon; usually organizes with other terrorists in small cells; often uses religion as a cover for terrorist activities

Source: WordNet (r) 2.0
 

Terrorist \Ter"ror*ist\, n. [F. terroriste.]

One who governs by terrorism or intimidation; specifically, an agent or partisan of the revolutionary tribunal during the Reign of Terror in France. --Burke.

Source: Webster's Revised Unabridged Dictionary (1913)