nighten

verb

1. (intransitive)To become night or grow dark, as night.

   “The flame of these smudge pots was just the type which presented itself in my vision, fluttering like a flag and giving off enough dark smoke to nighten the wooden sculpture above and around the flame.”

   “A flash of pretty fireworks in a nightening sky falling down, making the dry field catch fire.”

   “A dark place, a shadowed place, only a blot against the eternally nightened skies.”