いい子こちゃん

expression, noun

goody-goody; teacher's pet; goody two-shoes

Colloquial, often mildly derogatory term for someone who acts overly well-behaved or tries too hard to be seen as good, especially in school or social settings.

• 彼かれはいつも先せん生せいに気きに入いられようとしていて、クラスメートからいい子こちゃん扱あつかいされている。

  He's always trying to get in the teacher's good books, so his classmates treat him like a teacher's pet.

• そんなにいい子こちゃんぶらなくてもいいよ。

  You don't have to act like such a goody-goody.