a goody-goody

a goody-goody

someone who tries too hard to please people in authority, especially teachers or parents Sandra's a real goody-goody - always doing extra homework and arriving early to lessons.
References in classic literature ?
Aren't you ashamed of being such a goody-goody, and of studying so hard?
Similarly, a goody-goody teacher seems to be the unique professional--one with a fantastic figure--but empty-minded.