darken

1. V-T/V-I If something darkens or if a person or thing darkens it, it becomes darker. 变暗; 使变暗

The sky darkened abruptly. 天突然变暗了。

2. V-T/V-I If someone's mood darkens or if something darkens their mood, they suddenly become unhappy. 黯淡; 使黯淡[文学性]

My sunny mood suddenly darkened. 我快乐的情绪突然黯淡下来。