agitator
One who agitates; one who stirs up or excites others, for example political reformers.
Other meanings
An implement for shaking or mixing.
One of a body of men appointed by the army, in Oliver Cromwell's time, to look after their interests.
Where this comes from
This definition is adapted from “agitator” on Wiktionary, by its contributors, published under CC BY-SA 4.0. This page is published under the same licence.