underage

1. ADJ A person who is underage is legally too young to do something, for example to drink alcohol, have sex, or vote. (人)未到法定年齡的

Underage youths can obtain alcohol from their older friends. 未到法定年齡的孩子可以從他們年長的朋友那裡得到酒。

2. ADJ Underage activities such as drinking or smoking are carried out by people who are legally too young to do them. (行爲)未到法定年齡的[ADJ n]

...his efforts to stop underage drinking and drug abuse. ...他阻止未到法定年齡的人喝酒和吸毒的努力。