an officer of the peace, having police and minor judicial functions, usually in a small town, rural district, etc.

Chiefly British . a police officer.

an officer of high rank in medieval monarchies, usually the commander of all armed forces, esp. in the absence of the ruler.

the keeper or governor of a royal fortress or castle.

noun

bluecoat , finest , officer , patrolman , patrolwoman , peace officer , police , police officer , policewoman