a.

1. 红的，红色的
   I prefer the green sweater to the red one.

   我喜欢那件绿毛衣胜过红的那件。

2. （毛发）红褐色的
3. 通红的，充血的
   The little girl's eyes were red with weeping.

   那个小女孩哭得两眼通红。

4. （酒）紫红色的
5. 流血的，暴力的，沾有鲜血的

n.

1. 红，红色[C][U]
2. 红衣服[U]
   The girl in red is his younger sister.

   那个穿红衣服的女孩是他妹妹。

3. 赤字，负债，亏损[the S]

adj.

1. of a colour at the end of the spectrum next to orange and opposite violet, as of blood or rubies.
   ▸(of hair or fur) of a reddish-brown colour.
   ▸(of a person's face) red due to embarrassment, anger, or heat.
   ▸dated or offensive (of a people) having reddish skin.
2. (of wine) made from dark grapes and coloured by their skins.
3. of or denoting the suits hearts and diamonds in a pack of cards.
4. denoting a red light or flag used as a signal to stop.
   ▸denoting something forbidden, dangerous, or urgent.
5. (of a ski run) of the second-highest level of difficulty.
6. informal, chiefly derogatory communist or socialist.
7. archaic or literary involving bloodshed or violence.

n.

1. red colour or pigment.
2. informal, chiefly derogatory a communist or socialist.
3. (the red) the situation of having spent more than is in one's bank account.