/tə ˈsmʌɡəl meɪl/ – Phrase
Definition: chuyển lén thư từ (vào trại giam và từ trại giam ra).
A more thorough explanation: “Smuggle mail” refers to the act of illegally importing or exporting mail or postal items without proper authorization or in violation of postal regulations.
Example: The defendant was charged with attempting to smuggle mail across the border without proper authorization.