noun
ringleader
RING-lee-der/ˈrɪŋliːdər/
The main organizer of a group involved in wrongdoing.
The ringleader directs friends to throw paper balls into the school doorway.

Etymology
Leading the ring meant being foremost in a group, probably extending an image of leading a circle of dancers. The term came to apply especially to someone directing others in wrongdoing.
In context
When another attempt to get Lincoln at the Ford’s Theatre failed on the 29th of March, the ringleader was so low he told his minions he was giving up on the undertaking entirely.
More examples
- Police arrested the ringleader of the fraud scheme.
- The principal identified two ringleaders behind the cafeteria vandalism.
- Although everyone joined the prank, Maya was the ringleader.
Forms
ringleader · ringleaders
Similar words
- mastermind
- Emphasizes planning a complex scheme rather than leading its participants.
- instigator
- Starts trouble but may not direct the group's later actions.