nighten

From night +‎ -en.

nighten (third-person singular simple present nightens, present participle nightening, simple past and past participle nightened)

1. (intransitive) To become night or grow dark, as night.
   • 1996, Frederick Kiesler, ‎Siegfried Gohr, ‎Gunda Luyken, Frederick J. Kiesler: selected writings, page 60:

     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.

   • 2005, David White, The Hallucinogenic Rooster, page 163:

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

   • 2014, Harlan Ellison, Paingod:

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

• henting