adjective Date: 1944 protected by a high degree of secrecy , 2. containing or being information whose unauthorized disclosure could result in exceptionally grave danger to the nation , of or relating to ~ documents
TOP SECRET
Meaning of TOP SECRET in English
Merriam Webster. Explanatory English dictionary Merriam Webster. Толковый словарь английского языка Мерриам-Уэбстер. 2012