Agitator (noun)

1. A person who tries to stir up public opinion or make people excited or angry.
2. A person who tries to incite or organize resistance or rebellion against a government or authority.
3. A machine or device that agitates, as in washing machine.

Origin:

Late middle english, from latin agitator, from agitare to drive, set in motion.

Examples:

1. He was labeled as an agitator for his role in organizing the strike.
2. She was considered an agitator for her vocal opposition to the government's policies.
3. The agitator in the washing machine helps to move the clothes around.
4. The agitator in the paint mixer helps to blend the paint.
5. The agitator in the cement mixer helps to mix the cement.