alien
noun /ˈeɪliən/
  /ˈeɪliən/
- (North American English also non-citizen)(law or specialist) a person who is not a citizen of the country in which they live or work
- an illegal alien
 
Extra ExamplesTopics Social issuesb2, Crime and punishmentb2- During the war, he was imprisoned as an enemy alien.
 - It is illegal for employers to hire aliens not authorized for employment.
 - The provisions would broaden the government's ability to deport aliens.
 
Oxford Collocations Dictionaryadjective- enemy
 - illegal
 - undocumented
 - …
 
- deport
 - apprehend
 - arrest
 - …
 
 - a creature from another world
- aliens from outer space
 
Extra ExamplesTopics Spaceb2- Do you genuinely believe that space aliens have landed on our planet?
 - Few movies represent intelligent aliens as physically different from humans.
 - He was convinced that he'd been abducted by aliens.
 - In the movie aliens invade Earth.
 
Oxford Collocations Dictionaryadjective- space
 - giant
 - intelligent
 - …
 
- abduct
 - kidnap
 - invade
 - …