n.

1. 微明；薄暮；微光[U]
2. 黄昏；黎明[U]
   These animals begin the night's hunt at twilight.

   这些动物在黄昏时分开始一夜的觅食。

3. 衰退期；（人的）暮年，晚期[the S]
   The old man is in the twilight of his career.

   这老人已经进入了他生涯的晚期。

4. 朦胧状态；模糊状态[S]
   For three days the patient lay in a twilight of fever.

   病人发烧整整三天，一直迷迷糊糊。

a.

1. 曙暮光的；微明的；昏暗的
2. 衰落时期的；暮年的，晚期的
   The old man spent most of his twilight years working on his autobiography.

   老人暮年的大部分时间都在写他的自传。

n.

1. the soft glowing light from the sky when the sun is below the horizon, caused by the reflection of the sun's rays by the atmosphere.
2. a period or state of obscurity or gradual decline:
   the twilight of his career.