(From the Jargon File) When used to describe a computer program, rude means that the program was badly written; functionally poor, e.g., a program that is very difficult to use because of gratuitously poor (random?) design decisions (oppose cuspy); or that the program manipulates a shared resource without regard for its other users in such a way as to cause a (non-fatal) problem. Examples: programs that change tty modes without resetting them on exit, or windowing programs that keep forcing themselves to the top of the window stack. Compare all-elbows.