to prevent someone from moving closer: He held the police at bay for several hours. keep something at bay idiom (also hold something at bay) to control something and prevent it from causing you problems:

hold/keep someone/something at bay idiom Add to word list C2 to prevent someone or something unpleasant from harming you: Exercise can help keep fat at bay.

at bay To keep someone or something at a safe distance. The phrase derives from stag hunting, from a French word that also is the source of the English word for the baying howl that hounds make during a chance. A tired and cornered stag that turns to face the pursuing hounds is, for the moment, at a safe distance from its attackers.