もう大人だ

already an adult

→ もう

phrase Rare #24,110

already an adult Used to say that someone is now considered an adult or has grown up. もう means “already” or “now,” and だ is the plain form of “to be.”

JA: もう大人だから、自分で決めなさい。

EN: You're an adult now, so decide for yourself.

君はもう大人だ。

You're an adult now.

僕ももう大人だ。

I'm an adult now, too.

今日、君がついたウソを許そう君は混乱した子供だったからでも、今はもう大人だ

I’ll forgive the lie you told today because you were a confused child—but now you’re an adult.

— ダーク・プレイス (2015)

お前もゆうべからもう大人だ

You're an adult too, as of last night.

— 七人の侍 (1954)

僕はもう大人だよ

I'm an adult now.

— ラブ・アクチュアリー (2003)