This term is usally given to Native Americans that do not speak with a 'rez' accent and/orgrew up in a city. (As oppose to growing up on a reserve).
This term is usually used amongst Native Americans to insultother Native Americans.
An urban born First Nation walks by a group of reserve born First Nations...
"Everyone know's he's an apple."
(Apple also applies to this same slur)
"Everyone know's he's an Indian Crab."