Instigator

Noun

 * 1) A person who intentionally incites or starts something, especially one that starts trouble.

Synonyms

 * initiator

Thesaurus
agent, agent provocateur, agitator, agitprop, ancestors, apprentice, architect, artificer, artist, author, begetter, beginner, builder, catalyst, causer, conceiver, constructor, craftsman, creator, demagogue, designer, deviser, discoverer, effector, engenderer, engineer, exciter, executor, executrix, father, firebrand, fomenter, founder, generator, grower, inaugurator, incendiary, inciter, industrialist, inflamer, initiator, inspirer, institutor, introducer, inventor, journeyman, maker, manufacturer, master, master craftsman, mischief-maker, mother, mover, organizer, originator, parent, past master, planner, precursor, prime mover, primum mobile, producer, provocateur, provoker, rabble-rouser, raiser, realizer, ringleader, rouser, seditionary, seditionist, shaper, sire, smith, troublemaker, urger, wright

Etymology
From instigator:

Related terms

 * instigate
 * instigation