/əˈfɪʃəl ˈsiːkrɪt/ – Phrase
Definition: bí mật công tác, bí mật quốc gia.
A more thorough explanation: An official secret refers to information that is classified or designated as confidential by a government or other official entity, and is protected by law from disclosure to unauthorized individuals or the public.
Example: The government employee was charged with leaking an official secret to the press.
