verb

watch over in order to protect or control.

two men were left to guard the stockade

protect,stand guard over,watch over,look after,keep an eye on,take care of,cover,patrol,police,defend,shield,safeguard,preserve,save,keep safe,secure,screen,shelter,fortify,garrison,barricade,man,occupy

noun

a person who keeps watch, especially a soldier or other person assigned to protect a person or to control access to a place.

a security guard

sentry,sentinel,security guard,nightwatchman,protector,defender,guardian,custodian,keeper,scout,lookout,watch,garrison,bouncer,watchman