provoker
1. [ noun ] someone who deliberately foments trouble
Synonyms: inciter instigant firebrand instigator
Examples:

"she was the instigator of their quarrel"

Related terms: troublemaker ringleader harass incite
Similar spelling:   provoke
  provoked
  provoking
  provos
  provost
  proviso
  previse
  provokingly
  previous