1. a person who leads or organizes a group engaged in illegal or disruptive activities

Examples

• The police arrested the ringleader of the theft operation.
• She was identified as the ringleader of the student protest.
• The ringleader convinced the others to participate in the scheme.
• Without their ringleader, the group quickly disbanded.
• The ringleader was sentenced to five years in prison.
• Teachers suspected him of being the ringleader behind the pranks.