公こう然ぜんの秘ひ密みつ

expression, noun

open secret

Refers to something that is officially secret but widely known or obvious to many people.

• 彼かれの退たい職しょくは公こう然ぜんの秘ひ密みつだった。

  His resignation was an open secret.

• その会かい社しゃの不ふ正せいは業ぎょう界かいでは公こう然ぜんの秘ひ密みつだ。

  The company's misconduct is an open secret in the industry.