J.K. Rowling used the term Muggle for a person without magical ability in the Harry Potter books.
A Muggle is generally someone who is not born into or capable of practicing magic. The books use the word for ordinary non-magical people, including Harry’s aunt and uncle, although Harry himself is a wizard despite being raised in a Muggle household.
The word is different from “Squib.” A Squib is born into a wizarding family but lacks magical ability, while a Muggle has no magical ancestry in the usual sense. “No-Maj” is the term used in the American setting of Fantastic Beasts.
Rowling’s use of “Muggle” made the term part of everyday popular culture. It has also been added to some English dictionaries, where it can describe an inexperienced or non-specialist person in a broader sense.