alien vs interloper

alien

noun
  • One excluded from certain privileges; one alienated or estranged. 

  • Any life form of extraterrestrial or extradimensional origin. 

  • A foreigner residing in a country. 

  • A person, animal, plant, or other thing which is from outside the family, group, organization, or territory under consideration. 

adj
  • Not belonging to the same country, land, or government, or to the citizens or subjects thereof; foreign. 

  • Very unfamiliar, strange, or removed. 

  • Pertaining to extraterrestrial life; typical of an extraterrestrial creature. 

verb
  • To estrange; to alienate. 

  • To transfer the ownership of something. 

interloper

noun
  • One who interferes, intrudes or gets involved where not welcome, particularly a self-interested intruder. 

How often have the words alien and interloper occurred in a corpus of books? (source: Google Ngram Viewer )