perp + Add to list perp Slang EtymologyEtymology 1 Clipping of perpetrator.Etymology 2 Clipping of perpetual futures or perpetual bond. Idioms1 entry01perp walkThe intentional public display before news cameras of a person in police custody, especially someone famous or notorious, for the purpose of satisfying public interest, demonstrating the effectiveness of the authorities, or shaming the person.