“適得其反”，漢語成語，意思是恰恰得到與預期相反的結果（The result was just the opposite.）。可以翻譯爲“run counter to one's desire或have an exactly opposite effect”。
例句：
其結果必然不會像他們所想得那樣，而只能適得其反。
The result will definitely turn out to be just the opposite of their wish.
總統的策略可能會適得其反。
The president's tactics could backfire.