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English definition of “alien”

alien

noun [C]     /ˈeɪ.li.ən/
specialized law someone who lives in a country of which they are not a legal citizen: When war broke out the government rounded up thousands of aliens and put them in temporary camps .Racial issuesRace and ethnicity a creature from a different planet Strange, suspicious and unnatural things and people
(Definition of alien noun from the Cambridge Advanced Learner's Dictionary & Thesaurus © Cambridge University Press)
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