n.
1.a person who keeps watch over something or someone
2.the person who plays that position on a football team
3.a device designed to prevent injury
4.a posture of defence in boxing or fencing
5.the person who plays the position of guard on a basketball team
6.a group of men who escort and protect some important person
7.a precautionary measure warding off impending danger or damage or injury etc.
8.the duty of serving as a sentry
9.a position on the line of scrimmage 10.a position on a basketball team guard v.
1.to keep watch over
2.watch over or shield from danger or harm
3.protect against a challenge or attack
4.take precautions in order to avoid some unwanted consequence