guard

1.a person who keeps watch over something or someone

2.the person who plays that position on a football team;

the left guard was injured on the play

3.a device designed to prevent injury

4.a posture of defence in boxing or fencing;

keep your guard up

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.;

he put an ice pack on the injury as a precaution

8.the duty of serving as a sentry;

he was on guard that night

9.a position on the line of scrimmage;

guards must be good blockers

10. a position on a basketball team

1.to keep watch over;

there would be men guarding the horses

2.watch over or shield from danger or harm; protect;

guard my possessions while I'm away

3.protect against a challenge or attack;

Hold that position behind the trees!

4.take precautions in order to avoid some unwanted consequence;

guard against becoming too friendly with the staff