Darken (verb)

1. Become dark or darker.
2. Make dark or darker.
3. Cause to appear gloomy or menacing.

Origin:

Old english dearcian, from deorc "dark".

Examples:

1. The sky began to darken as the storm approached.
2. He darken the room by closing the curtains.
3. The bad news darken his mood.
4. The room darken as the sun set.
5. The mood in the room darken as the topic of conversation turned to politics.