immature

Tu es immature.

You're immature.

Tom est immature.

Tom is childish.

C'est si immature.

That's so immature.

Elle est jeune et immature.

She is young and immature.

Arrête d'être aussi immature.

Stop being so immature.

Je pense que tu as été très immature.

I think you've been very immature.

À l'entendre, il semble très immature.

He sounds very immature.

C'était très immature de sa part de se comporter ainsi.

It was childish of him to behave like that.