Translation of "Brat" in Japanese

For a brat, you've said something very mature.

がきにしては、随分大人びたことを言ったな。

You shouldn't allow your son to act like a selfish brat.

息子にわがままさせてはいけないよ。

A 40- or 50-year-old is a snot-nosed brat.

四十五十は鼻たれ小僧。

Thanks, I hear you've been taking care of my little brat of a brother.

ども、愚弟がお世話になってるようで。

- Keep your son from having his own way.
- You shouldn't allow your son to act like a selfish brat.
- You shouldn't allow your son to always have his own way.

息子にわがままさせてはいけないよ。