Any person that has not been baptized and does not plan on it. This nickname is the result of the creation of the nickname Doughtnut, as well as others like Waffle, Bagel, and French Toast. (Look only at the definitions provided by 'Relic' to see what each means when used as a nickname.)
She is definately a muffin; you can see it in her eyes. Not only that, though, but she told me she was yesterday.