n. 25B6; adjective
alien cultures : FOREIGN, overseas, non-native.
an alien landscape : UNFAMILIAR, unknown, strange, peculiar; exotic, foreign.
a vicious role alien to his nature : INCOMPATIBLE, opposed, conflicting, contrary, in conflict, at variance; rare oppugnant.
alien beings : EXTRATERRESTRIAL, unearthly; Martian.
native, familiar, earthly.
25B6; noun
an illegal alien : FOREIGNER, non-native, immigrant, emigrant, émigré, incomer.
the alien's spaceship crashed : EXTRATERRESTRIAL, ET; Martian; informal little green man.