WordNet sense 1 (anyone who does not belong in the environment in which they are found):

stranger, unknown

WordNet sense 2 (a person who comes from a foreign country; someone who does not owe allegiance to your country):

foreigner, noncitizen, outlander

WordNet sense 3 (a form of life assumed to exist outside the Earth or its atmosphere):

extraterrestrial, extraterrestrial being

WordNet sense 4 (transfer property or ownership):

alienate

WordNet sense 5 (arouse hostility or indifference in where there had formerly been love, affection, or friendliness):

disaffect, estrange

WordNet sense 6 (not forming an essential part of a thing or arising or originating from the outside):

extrinsic

WordNet sense 7 (being or from or characteristic of another place or part of the world):

exotic

WordNet sense 8 (relating to or originating in or characteristic of another place or part of the world):

foreign, strange