Looking up...
Un extraterrestre apparaît dans ce film de science-fiction.
An alien appears in this science-fiction film.
an alien being from another planet
Les enfants croient aux extraterrestres.
Children believe in aliens.
Un extraterrestre visite la Terre dans le film.
An alien visits Earth in the film.
relating to outer space, alien in nature
Ils étudient une forme de vie extraterrestre.
They are studying an extraterrestrial life form.
From extra- + terrestre.