From the usage common among Wiccan/Pagan groups (referring to a non-pagan). A person that's outside of the circle of knowledge/understanding. A non-tech/non-gamer/non-Unix/Non-windows/Non-BeOS/non-whatever (depending on your particular point of view). Also implies a guru/mystical status to the group using the term. Example: No mundane is going to load UNIX at home. He's not going to frag us in Quake. Up until last week he was just another mundane
MUNDANE
Meaning of MUNDANE in English
Slang English vocab. Английский сленговый словарь. 2012