Word

alien

noun C1

/ˈeɪ.li.ən/

Meanings

noun

a being from another planet

noun

a person who is not a citizen of the country where they are living or visiting

adjective

strange, unfamiliar, or not belonging in a particular place or situation

Definition

An alien is a person from another country or, in science fiction, a being from another planet.

An alien can refer to someone who is not a citizen of the country where they are living or staying. It is also commonly used to describe a life form from outer space in stories and films. More generally, it can describe something that feels unfamiliar or strange in a particular place or situation.

Examples

In the film, the alien communicates through shifting colors rather than spoken language.
As an alien in that country, I had to renew my visa before my research trip ended.
She found the startup’s jargon alien to her after years in public service.
They joked about spotting an alien when a strange light hovered over the lake at midnight.

Common mistake

Learners often misuse "alien" to mean "illegal" in general contexts, but it primarily means "foreign" (person) or "from outer space" (being).