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
Chad in Hilliard, Florida, wonders about the expression old as Methuselah, meaning “extremely advanced in years.” The phrase references Methuselah, a figure in Jewish, Islamic, and Christian tradition said to be 969 years old when he...
Carmen in Jacksonville, Florida, was told she was pretty as a speck of puff. The more common simile is pretty as a speckled pup or cute as a speckled pup. This is part of a complete episode.
Related
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.