guard

verb

• 1watch over in order to protect or control:two men were left to guard the stockade the gates were guarded by soldiers
• watch over (someone) to prevent them from escaping:his task was to help guard Japanese prisoners
• Basketball stay close to (an opponent) in order to prevent them getting or passing the ball: when a player is so closely guarded he cannot pass the ball

• 2protect against damage or harm:the company fiercely guarded its independence
• [no object] (guard against) take precautions against:farmers must guard against sudden changes in the market

noun

• 1a person who keeps watch, especially a soldier or other person assigned to protect a person or to control access to a place:a security guard [as modifier]:soldiers on guard duty
• [treated as singular or plural] a body of soldiers serving to protect a place or person:he’s the captain of the palace guard
• (Guards) the household troops of the British army.
• Irish a member of the Irish police force; a Garda: There’s bends all the way from Portlaoise to Carlow. The responsibility for speeding traffic rests with the guards
• North American a prison warder.

• 2a device worn or fitted to prevent injury or damage:a retractable blade guard

• 3 [in singular] a defensive posture that is adopted in a boxing or martial arts contest or in a fight:before Seb could raise his guard Boz swung a wild punch
• a state of vigilance or preparedness against adverse circumstances:he let his guard slip enough to make some unwise comments

• 4British an official who rides on and is in general charge of a train.

• 5 American Football each of two players either side of the centre.
• Basketball each of two players chiefly responsible for marking opposing players.