What's the difference between 成人 and 大人?


What's the difference between 成人 and 大人 ?




成人 is a very specific term and refers to persons who reached the age of 20 and
above. It's derived from the definition of the Japanese law, which says
"年齢二十歳をもって、成年とする".

You used to get drafted and taxed after this age. In today's context, it's the
legal drinking/smoking age.

大人 is a more lax term and usually means persons that are older than around 18
- 25 (depends on the context/speaker).

大人 is also used to mean "mature". For example, a toddler can be 大人 like this:

> A: 大樹君、３歳なのにお寺が好きなんだって！  
>  B: 大人～（笑）

You can't do this with 成人. It's also more formal than 大人 so it's much more
common to use 大人 in everyday speech. Also 成人になる specifically means "to turn
20". 大人になる usually means "to become mature".

> 芳一は来年成人になる -> OK  
>  芳一は来年大人になる -> Weird  
>  美緒もだんだん成人になってきたなぁ -> Weird  
>  美緒もだんだん大人になってきたなぁ -> OK




成人 is a very specific term and refers to persons who reached the age of 20 and
above. It's derived from the definition of the Japanese law, which says
"年齢二十歳をもって、成年とする".

You used to get drafted and taxed after this age. In today's context, it's the
legal drinking/smoking age.

大人 is a more lax term and usually means persons that are older than around 18
- 25 (depends on the context/speaker).

大人 is also used to mean "mature". For example, a toddler can be 大人 like this:

> A: 大樹君、３歳なのにお寺が好きなんだって！  
>  B: 大人～（笑）

You can't do this with 成人. It's also more formal than 大人 so it's much more
common to use 大人 in everyday speech. Also 成人になる specifically means "to turn
20". 大人になる usually means "to become mature".

> 芳一は来年成人になる -> OK  
>  芳一は来年大人になる -> Weird  
>  美緒もだんだん成人になってきたなぁ -> Weird  
>  美緒もだんだん大人になってきたなぁ -> OK

