VERB
令（自己）不自量力；使（自己）因目标过高而失败
If you say that someone overreaches themselves, you mean that they fail at something because they are trying to do more than they are able to.
例句
He overreached himself and lost much of his fortune...
他的雄心太大，结果损失了自己大部分的财产。
The company had overreached itself and made unwise investments...
这家公司不自量力地轻率投资。