too big for one's boots用来比喻一个人过度自我膨胀，最后连靴子或马裤都塞不下。要注意big用来表示抽象的意思时，除了可以当“浮夸”解释，还有“心胸宽大”的意思。

【例句】
He thought too much of himself and was getting too big for his boots, though he kept his thoughts to himself.
他少年得志，目中无人，不过没有表露出来。

Haas was a top student in his class, but now he is too big for his boots.
哈斯在班上是最好的学生，但现在他太目中无人了。