This is a whole other can of worms, but in the colloquial sense “expat” is a word a white immigrant uses to refer to themselves and other white immigrants. “Immigrant” is the term used for coloured people living in a different country than where they were born and grew up. The official definition for “expat” is a worker with temporary residency in a country for work; the person means to or has to return to their country of origin at some point. The term is rarely used like that though. Even if it were, we have the lovely “temporary foreign worker” or “guest worker” to refer to coloured or lower-class expats. So no matter which way you look at it the term “expat” is wrapped in racism.