roundsman (n.)

• bailiff
• beadle
• beagle
• captain
• commissioner
• constable
• deputy
• detective
• fed
• federal
• fireguard
• gendarme
• inspector
• lieutenant
• lookout
• marshal
• narc
• officer
• patrol
• patroller
• patrolman
• picket
• policeman
• policewoman
• reeve
• scout
• sentinel
• sentry
• sergeant
• sheriff
• spotter
• superintendent
• tipstaff
• trooper
• watch
• watcher
• watchman