1. (WWII military slang) Fucked up beyond all recognition (or repair).
Larry Robinson <firstname.lastname@example.org> reports the following nonstandard use for FUBAR:
One day somebody got mad at the card reader (or card eater that day) on our Univac 3200. He taped a sign, "This thing is FUBAR", on the metal weight that sits on the stack of unread cards. The sign stayed there for over a year. One day, somebody said, "Don't forget to put the fubar on top of the stack". It stuck! We called that weight the fubar until they took away the machine. The replacement card reader had two spring loaded card clamps, one for the feed and one for the return, and we called THOSE fubars until we dumped punch cards.
Incidently, the way he taped the sign on the weight made up for the lack of a little nylon piece that was missing from it, and fixed the card reader. That's why the sign stayed there.