The condition one finds oneself in after spending an appreciable amount of time in nithering conditions. The kind of cold where you can't feel your fingers, toes or nose any more, and don't look forward to them coming back, cos it'll hurt.
Person who only works at nite or person who is only functional at nite and may sleep all day. Similar to the Night Owl.
1. Dude is a total niter, you'll never see him out by daylite.
2. She only takes nite jobs, like club jobs cuz she's older than she says she is, she looks better in club lighting than in bright sunlite or office fluorescents.