Squaw was once an ordinary English word for a Native American woman or wife, and it is now widely treated as a slur. Do not use it. You need to recognise it, though, because it sits in a great deal of older writing — nineteenth-century novels, old Western films, and until recently hundreds of American place names, many of which have now been officially renamed. The word itself came from a real Algonquian word for 'woman', borrowed by English colonists in the 1620s, and the harm is not in its origin but in what English speakers did with it: centuries of using it dismissively, so it came to carry contempt. You may read online that it originally meant something obscene; that claim spread in the 1970s and linguists have shown it to be false — but the word is offensive anyway, and correcting the etymology does not make it usable. If you need to talk about the people, say 'a Native American woman', or better, name the nation: a Cherokee woman, an Ojibwe woman.