adjective
[more ~; most ~] :not familiar or like other things you have known :different from what you are used to
from another country :foreign
[more ~; most ~] :too different from something to be acceptable or suitable - + to
from somewhere other than the planet Earth
noun
plural aliens
[count] a person who was born in a different country and is not a citizen of the country in which he or she now lives
a creature that comes from somewhere other than the planet Earth