Definition of: alien

(āl′yən, ā′lē·ən) adjective
1. Of another country; foreign.
2. Of foreign character; not similar; incongruous; inconsistent; also, unsympathetic.
— noun
1. An unnaturalized foreign resident.
2. One of another race.
3. One estranged or excluded.
4. Bot. A plant native to one region maintaining itself under conditions prevailing in another.
—v.t.
1. To transfer to another, as property.
2. To estrange. [ < L alienus belonging to another] Synonyms (adj.): conflicting, contradictory, contrary, contrasted, distant, foreign, hostile, opposed, remote, strange, unconnected, unlike. Foreign refers to difference of birth, alien to difference of allegiance. In their figurative use, that is foreign which is remote, unlike, or unconnected; that is alien which is conflicting, hostile, or opposed. Antonyms: akin, appropriate, apropos, essential, germane, pertinent, proper, relevant. Synonyms (noun): foreigner, stranger. A naturalized citizen is not an alien, even if a foreigner by birth, and perhaps a stranger in the place where he resides. A person of foreign birth not naturalized is an alien, though he may have been long resident in the country, and ceased to be a stranger. He is an alien in one country if his allegiance is to another. Antonyms: citizen, countryman, native.