noun

1. Any life form of extraterrestrial or extradimensional origin.

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

3. A foreigner residing in a country.

Synonyms: outlander, fremd, guest, stranger

verb

1. To estrange; to alienate.

2. To transfer the ownership of something.

adjective

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

   “alien subjects, enemies, property, or shores”

2. Very unfamiliar, strange, or removed.

   “principles alien to our religion”

3. Pertaining to extraterrestrial life.