/ˈsiːkrɪt ˈɪnfərmənt/ – Phrase
Definition: người mật báo.
A more thorough explanation: A secret informant is an individual who provides information to law enforcement or other authorities about criminal activities or suspects, while keeping their identity confidential or undisclosed to the public.
Example: The prosecutor relied on information provided by a secret informant to build their case against the defendant.