The asterisk is often used in computer programming languages to represent a wildcard (one or more unknown characters). In computer gaming, a MUD (multi-user dungeon, dimension, or sometimes domain) is a multi-player computer game that combines elements of role-playing games, hack and slash style computer games, and social Internet Relay Chat channels. ... A MUSH (Multi-User Shared Habitat, or Hallucination) is a text-based online social medium to which multiple users are connected at the same time. ... Multiplex is either a word derived from multi- + plex (fold) or a synthetic portmanteau combining the words multiple and complex and can be another word for many or (literally) manifold. ... Moo can mean: MOO, a type of MUD text-based virtual reality system. ... Muck can refer to several different things: A type of soil: Muck (soil) An island in Scotland: Muck, Scotland Other meanings: A Multi-User Chat Kingdom (see MUD) To clean, as in to muck out A euphemism for manure Bottom sediments, as in a muckworm, a bottom dweller, also derisively... The term wildcard character has the following meanings: Telecommunication In telecommunications, a wildcard character is a character that may be substituted for any of a defined subset of all possible characters. ...
To answer a question with Mu (to say neither yes-nor-no) is to deny the validity of the question itself.
Mu is a call for the question to be unasked.
In fact, Mu is more extreme than this: It is a call to move beyond the limiting perspective of conceptualisation itself and to a directly contact with ultimate reality via pre-reflective awareness.