"Meaning of mom’s friends’ daughter" is "엄친딸"(ŏm-chin-ttal) in Korean.
It is abbreviation of “엄마 친구 딸 (Mother’s friend’s daughter)”. When the daughter of mom’s friend is the best in something in terms of face, education and etc. People try to inspire their children, to be derived from the fact that you speak as sarcasm. The more It think cumbersome that the child is compared with the others, the daughter of the mother of a friend always "honor student" is that.