大人おとなになる

expression, godan verb (-ru)

grow up; become an adult

Describes the process of reaching adulthood, both physically and socially. Often used in contexts of maturity and responsibility.

• 子こ供どもはいつか大人おとなになる。

  Children will grow up someday.

• 彼かれは大人おとなになって、医い者しゃになった。

  He grew up and became a doctor.