:in the position of being unable to move closer while attacking or trying to approach someone无法近身— used with keep or hold与keep或hold连用
The soldiers kept the attackers at bay. [=they did not allow the attackers to come closer]士兵们使进攻者无法靠近。
Armed with a gun, he held the police at bay [=he did not allow the police to arrest him] for 10 hours.由于有枪，他与警方僵持了10个小时。
— often used figuratively常用作比喻
Although the doctors had been able to keep her illness at bay [=to prevent her illness from becoming worse] for a few months, the disease soon began to spread again.尽管医生将她的病情控制住了几个月，可疾病不久又开始扩散了。