出处：按学科分类—语言、文字 中国对外翻译出版公司《汉英成语词典》第62页（313字）
①形容年纪虽然尚轻而处世却很老练，例他少年老成，堪当重任。
He’s young but mature and quite capable of taking on an important job．
②现也表示年轻人缺乏朝气，例小陈年纪不大，却已显得少年老成，暮气沉沉。
Xiao Chen might be young in age but he is lethargic and lacks vigour and drive