だめだよ

you can't

→ 駄目だ
phrase Uncommon #14,207
you can't Used to tell someone that something is not allowed or won't do. Depending on context, it can also mean that something has to be done.
JA: ここで写真を撮っちゃだめだよ。
EN: You can't take pictures here.

だめだよ

No, you can't.

— ウィキッド ふたりの魔女 (2024)

たき火で遊んじゃだめだよ。

Don't play with the campfire.

一人で行かなくっちゃだめだよ。

You have to go by yourself.

これはだめだよ

This is no good.

— The Wind Rises (2013)

病み上がりなんだから、無理しちゃだめだよ。

You’re just getting over being sick, so don’t overdo it.

ここにいたらだめだよシャワーを浴びてきなさい!

You can't stay here. Go take a shower!

— ライフ・イズ・ビューティフル (1997)

ああだめだよ

Ah, no, you can't.

— ロード・オブ・ザ・リング (2001)

だめだよ。

No, you can't.

一度や二度失敗したくらいで諦めちゃだめだよ。

You shouldn't give up just because you've failed once or twice.

ニーヤだめだよ

Niya, you can't do that.

— Arrietty (2010)

このピアノを弾いてもいいけど、夜はだめだよ。

You can play this piano, but not at night.

自分の力を過小評価しちゃだめだよ。

Don’t underestimate your own abilities.

空腹のままじゃだめだよ

You shouldn’t stay hungry.

— バジュランギおじさんと、小さな迷子 (2015)

それは修理しなくちゃだめだよ。

That needs to be repaired.