Mundane (also used in the form Mundie) is a term used to describe someone who is not part of the furry fandom. It is borrowed from the science fiction fandom, which shares equal definition, but for those who are not into science fiction. While technically a mere description, the term is often used to demean others.
Mundane is typically used sardonically toward others, not in the sense that one is "dull", but in the sense that one is not a furry. It is usually accompanied by an insulting tone, and can sometimes be the response of being ridiculed or mocked for involvement within the furry community. This term is most often used by lifestylers to describe those that do not share their connection to furries or animal spirituality. Lifestylers may even use this term to describe another furry who is not a lifestyler. It can also be used in the general sense, e.g. Mundanes wouldn't understand our ways, in which case it's more likely to be meant insultingly.