There could be any number of adjectives for 'Foreigner' (pron.
fore-uh-ner)
Old foreigner
young foreigner
asian foreigner
tall foreigner
short foreigner
fat foreigner
skinny foreigner
drunk foreigner
sober foreigner
white-haired foreigner
and so on . . . . BUT
If you meant "What is 'Foreigner' in adjective form?" the answer
would be, "Foreign".