1. (noun) someone who deliberately foments trouble

• firebrand
• inciter
• instigant
• provoker

2. (noun) a person who initiates a course of action

• initiator

1. (noun) someone who deliberately foments trouble

• ringleader

2. (noun) a person who initiates a course of action

• aggressor

1. (noun) someone who deliberately foments trouble

• bad hat
• mischief-maker
• trouble maker
• troublemaker
• troubler

2. (noun) a person who initiates a course of action

• leader

1. (noun) someone who deliberately foments trouble

• beset
• chevvy
• chevy
• chivvy
• chivy
• harass
• harry
• hassle
• molest
• plague
• provoke
• egg on
• incite
• prod
• incite
• incite
• incite
• instigate
• instigate
• instigate
• set off
• set off
• set off
• stir up
• stir up
• stir up

2. (noun) a person who initiates a course of action

• initiate
• pioneer
• inspire
• instigate
• prompt