A Native "Indian" (North American Aboriginal; First Nations; Indigenous; First Tribes; AmerIndian; American Indian; Canadian Indian; Native American; Native Canadian; Native North American; Mixed Blood; Half-Breed) person who is "red on the outside, white on the inside."
Sometimes said in jest or humor, but more often derogatory.
It means a First Nations ("red") person who is either full-blooded and "acts
white" (ie: wearing a suit and tie; working in an office; talks and acts and/or thinks "White".)
It could be said about a mixed-blood person who is part Native and Part Black or Asian or "other" non-Native ancestry, but only if they presented themselves as being savvy or invested in or involved in the so-called "White" system.
Can also mean a "half-breed" of half Native/half White ancestry (mainly said by Native people, either jokingly or derisively, or a bit of both.) It does NOT refer to a Métis person, as that is a culture unto itself (of half Native - often Cree - people and Whites - usually French-Canadian or from the North West U.S.)
Can also mean an "urban Indian" (a Native person who grew up off the Reserve mainly amongst non-Natives.)
Can also refer to a Native person who grew up in the foster care system and does not know his/her roots; or (in this context, can even be a veiled compliment) a Native person who takes part in "Native life" (pow wows, visits to family on the Reserve, "Red Power" politics, etc.) but has been educated in the "White" system and is as familiar with non-Native ways of life and thinking as with Native ways.
Our Chief talks about bringing back our traditional fishing rights, but he's just an apple who wants to "bed down" with The White Man and make some fast money.
She looks Japanese, but she's an apple - her Mom is Ojibway and her Dad is a White guy.
Professor Red Cloud Dancing is well-loved by his people (the Sioux) and those non-Natives at the University - he's a good apple.
Poor Johnny Big Deer - he grew up in the White foster care system, and he doesn't even know any other Native people - he's an apple.
That apple Mr. Abbotossaway is our boss in Accounting and Manager for The District, but he has family on the Reserve he sees regularly.