mount/stand/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 guard

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

stand guard

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

stand guard

Watch over, act as a lookout, as in We'll climb the tree and get the apples if Josh will stand guard, or There's a parking space; stand guard while I make a U-turn and get to it. This term alludes to the military defense of posting guards to watch for the enemy.
See also: guard, stand

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

stand guard

1. To keep watch.
2. To act as a sentinel.
See also: guard, stand