Originating from the Harry Potter books by JK Rowlings.
1)A non magical person
2)A 'normal' person
3) A person not involved or aware of your social circle's activities
Ex 1 & 2) Harry Potter's uncle, aunt, and cousin have no connections to the magical world or magical abilities, and are referred to as muggles.
3) A group of geocachers, role-players, harry potter fans speaking of a non-roleplayer/geocacher/harry potter fan etc... "I tried to explain it to her, but she was such a muggle. She didn't get it." or "Avoid the muggles, they're all over the park this afternoon."
1. "The Dursleys were what the wizards called Muggles (not a drop of magical blood in their veins)" (extract from 'Harry Potter And The Chamber Of Secrets', by J.K. Rowling).
2. (Said to employee at drive-through:) 'I'll have a Big Mac, fries, a Coke... (whispers:) and a dime bag of muggle(s)'.
3. 'Quick, five minutes before Math starts, let's muggle up!'
Any person who has no knowledge of the sport of Geocaching and who causes geocachers to become surreptitious about their activities in order to avoid a cache becoming exposed to non-geocachers. Also referred to as a GeoMuggles
The geocacher found what he knew must be the cache site, but waited until the muggles left so they would not see him and possiblyplunder the cache.