A word used by a cashier who has been working entirely too long. After completing a transaction and telling people all day "Have a great day!" but realizing that it is now dark outside, the cashier attempts mid-sentence to say "Have a great night."
Cashier: "Have a great (inside cashier's head: Dude, its 9pm)...d'night.."
(Customer looks confused and walks away, cashier feels stupid)