1. a person who regularly walks or travels around an area to watch for problems, provide security, or enforce rules

Examples

• The security patroller walked through the parking lot every hour.
• Border patrollers monitor the frontier for illegal crossings.
• A ski patroller rescued the injured snowboarder.
• The neighborhood patroller reported suspicious activity to police.
• Beach patrollers keep swimmers safe during busy summer days.
• The mall patroller checked that all stores were properly locked.
• Highway patrollers respond quickly to traffic accidents.