plainclothesman
- n a detective who wears civilian clothes on duty
- A plainclothesman who had interrogated Chessman the day after his arrest testified that he made several statements linking him to the red-light crimes, including an admission .
- At week's end, the former plainclothesman was awaiting trial in Rome's Queen of Heaven jail; Professor Gramantieri, in view of all the publicity, was thinking about a safer place .
- The plainclothesman watched laughing as the boy was put aboard a police truck.