n. a person who keeps watch over something or someone
n. the person who plays that position on a football team
n. a device designed to prevent injury or accidents
n. a posture of defence in boxing or fencing
n. 守卫者, 警戒, 护卫队, 防护装置
vt. 保卫, 看守, 当心
vi. 防止, 警惕, 警卫, 看守