Not belonging to the same country, land, or government, or to the citizens or subjects thereof; foreign; as, alien subjects, enemies, property, shores.
- Owing political allegiance to another country or government; foreign: alien residents.
- Belonging to, characteristic of, or constituting another and very different place, society, or person; strange. See Synonyms at foreign.
- Dissimilar, inconsistent, or opposed, as in nature: emotions alien to her temperament.
- An unnaturalized foreign resident of a country. Also called noncitizen.
- A person from another and very different family, people, or place.
- A person who is not included in a group; an outsider.
- A creature from outer space: a story about an invasion of aliens.
- Ecology An organism, especially a plant or animal, that occurs in or is naturalized in a region to which it is not native.
- Law To transfer (property) to another; alienate.