1. a person who breaks or injures someone's knees, typically as a form of violent punishment or intimidation
Usage: informal; often associated with organized crime or gang violence

Examples

• The crime boss hired a kneecapper to send a message to those who owed him money.
• In the noir film, the protagonist feared becoming a victim of the local kneecapper.
• The detective investigated reports of a kneecapper operating in the neighborhood.
• Witnesses described the kneecapper as a large man with a violent reputation.