In J. K. Rowling's Harry Potter series, a Muggle is a person who lacks any sort of magical ability and was not born in a magical family. Muggles can also be described as people who do not have any magical blood inside them. It differs from the term Squib, which refers to a person with one or more magical parents yet without any magical power/ability, and from the term Muggle-born, which refers to a person with magical abilities but with non-magical parents. The equivalent term used by the in-universe magic community of America is No-Maj, which is short for No Magic. The neologism, No-Maj was popular in the 1920s but soon went out of fashion and the original term, muggle came back into use before World War II and has been muggle ever since.
Usage in ''Harry Potter''
The term Muggle is sometimes used in a pejorative manner in the books. Since Muggle refers to a person who is a member of the non-magical community, Muggles are simply ordinary human beings without any magical powers and almost always with no awareness of the existence of magic. Hogwarts School of Witchcraft and Wizardry students who have non-magical parents are called muggle-borns. There have also been some children known to have been born to one magical and one non-magical parent. Children of this mixed parentage are called half-bloods; children with recent Muggle ancestry on the one side or the other are also called half-bloods. The most prominent Muggle-born in the Harry Potter series is Hermione Granger, who had two Muggles of unspecified names as parents. A witch or wizard with all magical heritage is called a pure-blood. In the Harry Potter books, non-magical people are often portrayed as foolish, sometimes befuddled characters, who are completely ignorant of the Wizarding world that exists in their midst. If, by unfortunate means, non-magical people do happen to observe the working of magic, the Ministry of Magic sends Obliviators to cast Memory Charms upon them, causing them to forget the event. Some Muggles, however, know of the wizarding world. These include Muggle parents of magical children, such as Hermione Granger's parents, the Muggle Prime Minister, the Dursley family, and the non-magical spouses of some witches and wizards. Rowling has stated she created the word "Muggle" from "mug", an English term for someone who is easily fooled. She added the "-gle" to make it sound less demeaning and more "cuddly".
Notable Muggles
The Dursleys, Harry's maternal relatives with whom he lived for sixteen years.
Mary Lou Barebone, leader of the New Salem Philanthropic Society
Other usages
The word muggle, or muggles, is now used in various contexts in which its meaning is similar to the sense in which it appears in the Harry Potter book series. Generally speaking, it is used by members of a group to describe those outside the group, comparable to civilian as used by military personnel. Whereas in the books muggle is consistently capitalized, in other uses it is often predominantly lowercase.
Muggle is used in informal English by Mensa members to define non-members or any person with IQ lower than Mensa level.
A muggle is, according to Abbott Walter Bower, the author of the Scotichronicon, "an Englishman's tail". In Alistair Moffat's book A History of the Borders from Early Times, it is stated that there was a widely held 13th-century belief amongst Scots that Englishmen had tails.
Ernest Bramah referred to "the artful Muggles" in a detective story published decades before the Potter books.
Published in 1982, Roald Dahl's character the Big Friendly Giant uses the word “Muggled” while describing a good dream to the other main character, Sophie - “And the whole school is then cheering like mad and shouting bravo well done, and, for ever after that, even when you is getting your sums all gungswizzled and muggled up, Mr. Figgins is always giving you ten out of ten and writing Good Work Sophie in your exercise book.” – The BFG. Roald Dahl also names a family of monkeys “The Muggle-Wumps” in The Twits and other writings.
Muggle is used in informal English by members of small, specialised groups, usually those that consider their activities to either be analogous to or directly involve magic to refer to those outside the group.
In online forums for people with herpes, Muggle is used to describe someone who does not have HSV.
Muggle is used by geocachers to refer to those not involved in or aware of the sport of geocaching. A cache that has been tampered with by non-participants is said to be plundered or muggled.