instigator

Definitions

A person who brings about or initiates something, especially something undesirable.

Someone who incites or urges others to take a particular action or course of conduct.

Examples

The police identified the main instigator of the riot after reviewing hours of security footage.

She was known as the instigator of many office pranks, always finding creative ways to stir up trouble.

Synonyms

provoker agitator inciter troublemaker firebrand rabble-rouser fomenter

Antonyms

peacemaker mediator pacifier conciliator suppressor soother stabilizer