Dictionary definition · guard
noun
- a person who keeps watch over something or someone
- the person who lines up between the center and the tackles on the offensive line of a football team on the line of scrimmage"the left guard was injured on the play"
- a device designed to prevent injury or accidents
- a posture of defence in boxing or fencing"keep your guard up"
- the person who plays the position of guard on a basketball team
- a military unit serving to protect some place or person
- a precautionary measure warding off impending danger or damage or injury etc."he put an ice pack on the injury as a precaution"
- the duty of serving as a sentry"he was on guard that night"
verb
- to keep watch over"there would be men guarding the horses"
- watch over or shield from danger or harm; protect"guard my possessions while I'm away"
- protect against a challenge or attack"Hold that position behind the trees!"
- take precautions in order to avoid some unwanted consequence"guard against becoming too friendly with the staff"
Source: Open English WordNet (CC BY 4.0).