How to say "grown-up" in Japanese

• 大人おとなJLPT N5approx.Common
  no-adjective, na-adjectiveThe word for a grown-up as a person: someone no longer a child. It is what you use when simply talking about adults, as when a child wants to be treated like a grown-up.
  大人おとなだけこの映画えいがが見みえる。↗

  Only adults can see this film.
• 成人せいじんJLPT N3approx.Common
  nounAdulthood as a legal or official status: a person who has come of age. For grown-ups in ordinary conversation this is seldom the word you want; use 大人 instead.
  その映画えいがは成人せいじんしかみられない。↗

  Only adults may watch that film.
• 大人っぽいおとなっぽいCommon
  i-adjectiveCovers 'grown-up' about manner, appearance, or behavior rather than a person: someone, often a child, who seems mature for their age. The adjective to reach for when English says someone acts or looks grown-up.
• 一人前いちにんまえCommon
  no-adjective, na-adjectiveA fully fledged grown-up: someone who has come of age and stands on their own. It stresses independence rather than age, so it is not the plain word for an adult.
  彼女かのじょも一人前いちにんまえの女おんなになった。↗

  She has grown up to be a woman.

Use 大人 for a grown-up as a person, 成人 for adulthood as a legal or official status, 「大人っぽい」 for grown-up manner or looks, and 一人前 for someone fully fledged and independent.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 大人おとなadult
• 成人せいじんadult
• 大人っぽいおとなっぽいgrown-up (manner, etc.)
• 一丁前いっちょうまえadult
• アダルティadult
• いっちょまえadult
• アダルティックadult
• 一人前いちにんまえadult
• ひとadult
• 大きいおおきいolder