老气横秋 -------- lacking in youthful vigor

例句：
A: Dick is lacking in youthful vigor in appearance. But in fact he is twenty-five years old.
迪克看起来老气横秋，实际上他才25岁。
B: No, he's not, is he? I don't believe It!
不会吧，我不相信。

同义词：
arrogant on account of one's seniority