口こう外がい

noun, noun or participle which takes 'suru', transitive verb

disclosure; revealing; telling

Used for revealing information or secrets, often with a nuance of something that should not be told. Common in negative or prohibitive expressions like 口外しない.

• この秘ひ密みつは絶ぜっ対たいに口こう外がいしないでください。

  Please never reveal this secret.