open secret
US /ˈoʊpən ˈsiːkrət/
UK /ˈoʊpən ˈsiːkrət/

1.
공공연한 비밀
a fact that is supposed to be secret but is actually known by many people
:
•
It's an open secret that they are planning to get married.
그들이 결혼할 계획이라는 것은 공공연한 비밀이다.
•
His affair with his assistant was an open secret in the office.
그의 비서와의 불륜은 사무실에서 공공연한 비밀이었다.