这使他们竞选时许下的诺言大打折扣。

This is a serious dilution of their election promises.

《牛津词典》

但是过期的苏打水跑气，味道也会大打折扣。

But soda past its expiration date goes flat and loses much of its taste.

《柯林斯英汉双解大词典》

最优秀的队员受了伤，使得这支队伍的实力大打折扣。

The team suffered a major setback when their best player was injured.

《牛津词典》