“无所不用其极”，原意是指尽一切努力，来达到的最高境界。现在表示为达到目的，不择手段，含贬义。可以翻译为“resort to every conceivable means, employ the meanest of tricks”。
例句：
为了博取上级的欢心，他无所不用其极。
He resorted to every conceivable means to win the favour of his superiors.
贪婪的老板为了攫取利润而无所不用其极。
The greedy boss stopped at nothing to gain profit.