relating to creatures from another planet.

strange and not familiar.

coming from a different country. race. or group.

a creature from a different planet.

someone who lives in a country of which they are not a legal citizen.

a person who lives in a country but is not a citizen (= member of a country with specific rights)

An alien is also a creature from a planet other than Earth.

coming from a different country. race. or group; foreign.

a person who lives in a foreign country of which they are not a citizen.