a.

1. 秘密的，机密的
   He kept his illness secret from his parents.

   他没有告诉他父母他生病的事。

2. 私下的，暗地里的[B]
   The political prisoner was executed after a secret trial.

   那名政治犯在受秘密审判后被处决了。

3. 隐蔽的，暗藏的
   He left through a secret door.

   他经由一道暗门离开。

4. 神秘的，奥秘的
5. 偏僻的；人迹罕至的
6. 嘴紧的，能保守秘密的[F][（+about）]
   He is secret about his past.

   他对自己早年的经历一向嘴紧。

n.[C]

1. 秘密，机密；内情
   I'll tell you a secret that I've never told a living soul.

   我要告诉你一个我从未告诉过任何人的秘密。

2. 神秘，奥秘[P]
3. 秘诀，诀窍；秘方[the S][（+of）]
   One of the secrets of good health is regular exercise.

   身体健康的诀窍之一是定时运动。

4. （人体）阴部[P]

adj.

n.

1. something kept or meant to be kept secret.
   ▸something not properly understood; a mystery:

   the secrets of the universe.
2. a way of achieving something, especially one that is not commonly known:
   the secret of a happy marriage is compromise.
3. a prayer said quietly by the priest after the offertory in a Roman Catholic Mass.