A goody-goody is someone who tries extra hard to be well-behaved, helpful, and “good,” mostly to please parents, teachers, or other grown-ups.

A goody-goody is someone whogoody-goody指的是那種人 tries extra hard to be well-behaved, helpful, and "good,"特別努力表現得乖、幫忙、『好』 mostly to please parents, teachers, or other grown-ups主要是想討好爸媽、老師或其他大人

Children use it most, and they almost never mean it kindly. It is a teasing, slightly sour word: the speaker thinks that person is showing off how good they are, or fishing for favour, not simply being decent.

Children use it most小孩子最常用這個字 and they almost never mean it kindly而且幾乎不是好意在講 It is a teasing, slightly sour word這是一個帶點揶揄、有點酸的字 the speaker thinks that person is showing off how good they are, or fishing for favour說話的人覺得那個人是在炫耀自己多乖，或是在討好處 not simply being decent而不是單純地做個正派的人

You hear it in the playground more than in a classroom essay. Adults can use it too, in a light, mocking way, about someone who always sits up straight and never breaks a small rule.

You hear it in the playground這個字在操場上比較常聽到 more than in a classroom essay比在課堂作文裡常見多了 Adults can use it too大人也會用 in a light, mocking way用一種輕鬆、帶點嘲弄的口氣 about someone who always sits up straight and never breaks a small rule說某個人總是坐得直挺挺、從不犯一點小規矩

It is informal. Though actually, the person may not be pretending at all — they may just like rules — but the word still paints them as too eager to please.

It is informal這是個非正式的字 Though actually不過實際上 the person may not be pretending at all那個人可能根本沒在假裝 — they may just like rules ———也許只是單純喜歡規矩—— but the word still paints them as too eager to please但這個字還是把他們講成太想討好別人