1. noun The forced walking of an arrested suspect or alleged criminal through a public space so as to allow him or her to be photographed or recorded on video. ("Perp" being short for perpetrator.) The photographers crowded the courtroom steps, eager to get a shot of the billionaire con artist as he began his perp walk.
2. verb (sometimes hyphenated) To force an arrested suspect to perform such a public walk. Police officers perp walked the actor through the crowd after he was arrested for allegedly beating up a reporter.