noun
underground school website; unofficial school message board
Refers to unofficial, often anonymous websites or online forums associated with a specific school, where students may share test info, gossip, or engage in cyberbullying. The term carries a negative, hidden-community connotation.
学校裏サイトでのいじめが問題になっている。
Bullying on underground school websites has become a problem.
彼は学校裏サイトに試験の過去問を投稿した。
He posted past exam questions on the underground school site.