/tə bi ˈʌndər ˈeɪdʒ/ – Phrase
Definition: vị thành niên, chưa đến tuổi trưởng thành.
A more thorough explanation: To be under (legal) age means to be below the age at which a person is legally considered an adult and is granted certain rights and responsibilities, such as the ability to enter into contracts, vote, or consume alcohol. The specific age at which a person is considered to be under legal age varies by jurisdiction.
Example: The defendant was found guilty of selling alcohol to a minor who was under the legal age of 21.