Alien = 外星人 [wài xīng rén]
A hot-air balloon with two big dark eyes drifts across the sky. It is a 外星人, arriving the slow way.
外星人 (wài xīng rén) means “alien” or “extraterrestrial.” 外 is outside, 星 is star, and 人 is person: a person from an outside star.
你相信有外星人吗？ — Nǐ xiāngxìn yǒu wàixīngrén ma? — Do you believe aliens exist?
他说他见过外星人。 — Tā shuō tā jiànguo wàixīngrén. — He says he has seen an alien.