alien vs essential

alien

adj
  • Very unfamiliar, strange, or removed. 

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

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

verb
  • To estrange; to alienate. 

  • To transfer the ownership of something. 

noun
  • 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. 

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

essential

adj
  • Really existing; existent. 

  • Necessary. 

  • Necessary for survival but not synthesized by the organism, thus needing to be ingested. 

  • Being in the basic form; showing its essence. 

  • Very important; of high importance. 

  • Having the nature of essence; not physical. 

  • Such that each complementary region is irreducible, the boundary of each complementary region is incompressible by disks and monogons in the complementary region, and no leaf is a sphere or a torus bounding a solid torus in the manifold. 

  • Idiopathic. 

noun
  • A necessary ingredient. 

  • A fundamental ingredient. 

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