極ごく内ない

noun

highly confidential; top secret

Used for information or matters that are strictly confidential, often in formal or official contexts.

• この書しょ類るいは極ごく内ない扱あつかいです。

  This document is treated as top secret.

• 極ごく内ないの情じょう報ほうを外がい部ぶに漏もらしてはいけない。

  You must not leak highly confidential information to outsiders.