foreigner
person not having citizenship in a country
foreign national
someone in a country who isn't a citizen or permanent resident
expatriate
individual temporarily or permanently residing in a country other than that of their citizenship
undocumented immigrant
immigrant resident of a state or country who does not possess appropriate legal documents associated with their status
metic
foreign resident of Athens, one who did not have citizen rights in their Greek city-state (polis) of residence
foreign worker
person working in a country other than one of which they are a citizen