When someone greets a person, but instantaneously finds out he doesn't really want to speak to that person anyway and quickly finds a way to say bye.
In some way the opposite of Hi-fived.
Guy 1: Hi
Guy 2: Hey Joe, are you still game for comparing our stamp-collections saturday?
Guy 1: Oh wait I gotta.... Bye.
Guy 2: That guy just hibyed me. :(