// Jim Shakes head as to say no.
// Bob makes a look as to say "Why not?"
// Jim makes a mater-of-factly look.
// Bob makes an understanding look.
Hackers tend to be sensitive to logical inadequacies in language, and many have adopted this suggestion with enthusiasm. The word "mu" is actually from Chinese, meaning "nothing"; it is used in mainstream Japanese in that sense, but native speakers do not recognise the Discordian question-denying use.
Thanks to Thrakem for the source of this definition.
Joshu retorted, "Mu!"
It is when a person is flirting with a member of the opposite sex whilst staring at their physical form. A witness or a friend of the person flirting must then say aloud the word "MU".
Friend 1: "That guy is totally MU-ing that woman"
Friend 2: "I know...MU!"
A friend witnessing a man flirting with a woman.
Friend (aloud): "MU!!!"