Synonym Nuance VS
How to say "Adult" in Japanese
Both words can translate to "adult", but which should you choose?
Japanese Option A
大人
おとな (otona)
N5 / CEFR Syllabus
VS
Japanese Option B
成人
せいじん (seijin)
N3 / CEFR Syllabus
Nuance Contrast & Translation Difference
When translating "adult" into Japanese, you must choose carefully between 大人 and 成人.
In Japanese, 大人 (おとな (otona)) is typically associated with "adult" (Syllabus Level: N5) and represents A noun meaning 'adult' or 'grown-up'. Often used in contrast to 子供.
On the other hand, 成人 (せいじん (seijin)) maps to "adult, full age" (Syllabus Level: N3) and represents A noun referring to a person who has reached the age of majority. A literal translation of "adult" can often sound unnatural to native Japanese speakers if mixed up!
Bilingual Context for "大人"
あの子供はもう大人になりました。
That child has already become an adult.
Bilingual Context for "成人"
日本では20歳で成人になります。
In Japan, you become an adult at 20 years old.
Nuance Mastery Quiz
Which Japanese word perfectly fits this blank space?
Fill in the blank: "あの子供はもう ＿＿＿ になりました。" (Meaning: "That child has already become an adult.")
🎉 Correct Answer!
Remember: "大人" fits here because it means "adult" in the context of: "That child has already become an adult.". "成人" represents "adult, full age".