Translation guide
The English word "alien" covers several distinct meanings: extraterrestrial beings, foreign nationals, and the adjective meaning unfamiliar or strange. Japanese uses different words for each, and direct translation can lead to unnatural phrasing.
Referring to a creature from outer space, as in sci-fi or UFO contexts.
The standard, neutral word for an extraterrestrial being. Literally 'space person'. Used in both casual and formal contexts.
宇宙人は本当にいると思いますか？
Do you think aliens really exist?
その映画には怖い宇宙人が出てくる。
A scary alien appears in that movie.
Loanword from English, often used in movie titles, games, or when emphasizing a menacing, monster-like alien. Carries a slightly more sci-fi/horror nuance than 宇宙人.
「エイリアン」は名作SFホラー映画だ。
"Alien" is a classic sci-fi horror movie.
Literally 'different star person'. A more literary or technical term, sometimes used in science fiction or formal writing. Less common in everyday speech.
異星人とのファーストコンタクトを描いた小説。
A novel depicting first contact with aliens.
Referring to a person who is not a citizen of the country, often in official or legal contexts.
The standard word for 'foreigner' or 'foreign national'. Neutral and widely used in daily life and official documents.
日本では多くの外国人が働いている。
Many foreign nationals work in Japan.
Specifically refers to foreign residents, often used in legal/administrative contexts regarding residence status.
在留外国人の数は年々増加している。
The number of foreign residents is increasing year by year.
Literary or poetic term for 'stranger' or 'foreigner', often with a nuance of being an outsider. Not used in everyday conversation.
Describing something that is not familiar, feels foreign, or is hard to understand.
Means 'different in nature', 'foreign', or 'alien' in the sense of being incongruous or not belonging. Often used for abstract concepts or atmospheres.
彼の考え方は私には異質に感じられた。
His way of thinking felt alien to me.
Literally 'without familiarity'. A common, natural way to say 'unfamiliar' or 'alien' when something is not known or experienced.
なじみのない土地での生活は大変だ。
Living in an unfamiliar (alien) land is tough.
Means 'strange', 'eerie', or 'uncanny'. Used when something feels weird or unnatural, close to 'alien' in a creepy sense.
異様な雰囲気が部屋に漂っていた。
An alien atmosphere hung over the room.
A phrase meaning 'far removed from oneself', used to describe ideas or values that feel completely alien.
彼の価値観は自分とはかけ離れている。
His values are completely alien to me.
Describing something related to extraterrestrial beings or outer space.
Use the possessive form of 宇宙人 to mean 'alien' as an adjective, e.g., 'alien technology'.
宇宙人のテクノロジーは想像を超えている。
Alien technology is beyond imagination.
Means 'extraterrestrial', often used in scientific or formal contexts.
地球外生命体の存在が確認された。
The existence of extraterrestrial life was confirmed.
While 外国人 means 'foreigner', it never refers to space aliens. Using it in a sci-fi context would cause confusion. Stick to 宇宙人 or エイリアン for extraterrestrial beings.
宇宙人 is the everyday word for any being from outer space. エイリアン is a loanword that often implies a hostile or monstrous creature, heavily influenced by the movie franchise. Use 宇宙人 for neutral or friendly aliens.
English uses 'alien' as an adjective freely (alien culture, alien concept). In Japanese, you usually need to use a phrase like 異質な, なじみのない, or 宇宙人の depending on the meaning. Avoid literal translation with a single adjective.
彼は異邦人のように街をさまよった。
He wandered the streets like a stranger.