n.

1. 哨兵；卫兵；警备员；看守员[C]
   A guard was placed at the door.

   门口设了一个警卫。

2. 护卫队[the S][G]
   A heavy guard remained around the building.

   建筑物周围一直有重兵守卫。

3. （常大写）（英国等的）皇家禁卫军[the P][G]
4. 守卫；警戒；看守[U]
   A policeman kept guard over the prisoners.

   一名警察看守囚犯。

5. 防护物[C]
6. 【英】（火车的）列车长[C]
7. （拳击等的）防御姿势，防守[U]
8. 【篮】后卫

vt.

1. 保卫；守卫；警卫[（+against/from）]
   A helmet guards your head against/from injuries.

   头盔可以保护你的头部免受伤害。

   A dog guarded his house.

   一只狗守卫着他的房子。

2. 看守；监视
3. 控制；使（言词等）谨慎
   You must guard your tongue carefully.

   你说话必须小心谨慎。

vi.

1. 防范；警惕[（+against）]
   You should wash your hands before eating, to guard against disease.

   你饭前应洗手，以防生病。

2. 守卫；看守

v.

1. watch over in order to protect, control, or restrict.
   ▸Basketball  stay close to (an opponent) to prevent them getting or passing the ball.
2. prevent from being harmed.
   ▸ (guard against) take precautions against.

n.

1. a person, especially a soldier, who guards or keeps watch.
   ▸N. Amer. a prison warder.
2. [treated as sing. or pl.] a body of soldiers serving to protect a place or person.
   ▸ (Guards) the household troops of the British army.
3. a device worn or fitted to prevent injury or damage.
4. a defensive posture adopted in a fight.
   ▸vigilance against adverse circumstances:

   he let his guard slip.
5. Brit. an official who rides on and is in general charge of a train.
6. Basketball  each of two players chiefly responsible for marking opposing players.
7. American Football  each of two players either side of the centre.