这些名词均有“年轻人，青少年”之意。
youth : 现在几乎专指男青年，尤指10多岁到20多一点的男青年，但作为集合名时间男女青年都可指。
- I was a fairly good football player in my youth.
我年轻时是个相当不错的足球运动员。 - The first volume is the author's account of his misspent youth in the bars of Dublin.
第一卷是作者对他在都柏林酒吧里虚度青春的叙述。 - He looks like a man who's found the secret to eternal youth (= staying young).
他看上去似乎掌握了永葆青春的秘诀。 - You may not have played tennis as often as him, but at least you've got youth on your side (= you are young).
你可能没像他那样经常打网球，但至少你有年轻的优势。
teenager : 主要指13岁到19岁之间的青少年，强调这个年龄段的人的本身特点。
- The magazine is aimed at teenagers and young adults.
这份杂志的读者对象是青少年和二十来岁的年轻人。
adolescent比teenager正式，侧重年龄。
- It is important that an adolescent boy should have an adult in whom he can confide.
关键是，青春期的男孩身边应该有一个可以交心的成年人。 - Parents worry about the effect of music on their adolescent's behavior.
父母担心音乐对青春期孩子的行为所产生的影响。
juvenile : 指青少年，系法律上的常用词。
- Juvenile crime is increasing at a terrifying rate.
青少年犯罪正在以惊人的速度增长。 - He is an expert in juvenile delinquency.
他是研究青少年犯罪的专家。 - This juvenile offender received no more than a judicial slap on the wrist.
这名少年犯只被从轻处惩了一下。
