adj. & n.
--adj.
1. a (often foll. by to) unfamiliar; not in accordance or harmony; unfriendly, hostile; unacceptable or repugnant (army discipline was alien to him; struck an alien note). b (often foll. by from) different or separated.
2 foreign; from a foreign country (help from alien powers).
3 of or relating to beings supposedly from other worlds.
4 Bot. (of a plant) introduced from elsewhere and naturalized in its new home.
--n.
1. a foreigner, esp. one who is not a naturalized citizen of the country where he or she is living.
2 a being from another world.
3 Bot. an alien plant.
Derivatives:
alienness n.
Etymology: ME f. OF f. L alienus belonging to another (alius)