keep guard

keep guard

To watch over someone or something; to act as a guard or a lookout for someone or something. He kept guard outside the bathroom to make sure no one walked in on Jeremy getting sick. The police are keeping guard around the prison, lest the prisoner should attempt escape a second time.

See also: guard, keep

mount/stand/keep ˈguard (over somebody/something)

act as a guard: Two soldiers stood guard over the captured weapons.

See also: guard, keep, mount, stand