adjective

1. belonging to another country or people; foreign
2. strange; not natural cruel words alien to his lips
3. opposed or repugnant beliefs alien to one's religion
4. of aliens

Etymology: ME & OFr < L alienus < alius, other: see else

noun

1. a foreigner
2. a foreign-born resident in a country who has not become a naturalized citizen
3. an outsider
4. in science fiction, a being in or from outer space and not native to the Earth; extraterrestrial

transitive verb

Etymology: ME alienen < OFr aliener < L alienare