muggle
n.— Note: Borrowed from J.K. Rowling’s books about Harry Potter. «He glanced around to make sure no muggles were watching. UF’s campus is crawling with muggles, the term for those oblivious to the worldwide scavenger hunt known as geocaching.» —“High-tech hunt” by Jessie Coleman in University of Florida-Gainesville Alligator Oct. 17, 2006. (source: Double-Tongued Dictionary)
Further reading
Sarah in Fleming Island, Florida, is curious about the saying sometimes you eat the bear, and sometimes the bear eats you, which suggests “it’s a dog-eat-dog world,” or “eat or be eaten,” or more gently, “you win...
Daniel in Gainesville, Florida, shares a funny story about people who misunderstood a party invitation that called for Sunday-to-meeting clothes. In this case, the meeting isn’t just any meeting. It’s an old word for “church...
Is being used by other affinity groups to refer to non-initiates. e.g., in fandom for non-fannish people. Very similar in usage to the longstanding use of “mundane” as a noun.