1. 仁慈;怜悯;宽恕
    If someone in authority shows mercy, they choose not to harm someone they have power over, or they forgive someone they have the right to punish.

    e.g. Neither side took prisoners or showed any mercy...
           双方都没有抓俘虏，也没有表现出丝毫的心慈手软。
    e.g. They cried for mercy but their pleas were met with abuse and laughter...
           他们哭喊着请求宽恕，可是他们的恳求却遭到了谩骂和嘲笑。

2. 慈善的;救援的
    Mercy is used to describe a special journey to help someone in great need, such as people who are sick or made homeless by war.

    e.g. She vanished nine months ago while on a mercy mission to West Africa...
           9个月前她在去西非的慈善之旅中消失了。
    e.g. It's the first so-called mercy flight for a fortnight as the Americans have been waiting for enough people to fill a 747 jet.
           美国人一直在等人坐满一架747飞机，这便是第一次为期两周的所谓慈善飞行。

3. 幸运;侥幸
    If you refer to an event or situation as a mercy, you mean that it makes you feel happy or relieved, usually because it stops something unpleasant happening.

    e.g. It really was a mercy that he'd died so rapidly at the end...
           他最后去得那么快，真是谢天谢地。
    e.g. The two cars finished up in a run-off area, clear of the circuit, and that was a mercy.
           两辆车最后都停在了缓冲区，避开了赛车道，真是万幸。

4. 完全由…支配;任由…摆布
    If one person or thing is at the mercy of another, the first person or thing is in a situation where they cannot prevent themselves being harmed or affected by the second.

    e.g. Buildings are left to decay at the mercy of vandals and the weather...
           建筑物因人为的肆意破坏及日晒雨淋而日益破败。
    e.g. The Emperor must realize that he has us at his mercy.
           皇帝必须意识到我们任由他处置。

5. 为坏情况没有变得更糟而庆幸
    If you tell someone who is in an unpleasant situation that they should be grateful or thankful for small mercies, you mean that although their situation is bad, it could be even worse, and so they should be happy.

mercy的解释

    e.g. But so low has morale sunk that the team and the fans would have been grateful for small mercies.
           士气如此低沉，一丁点的好运都会让队员和球迷庆幸不已。

6. 听凭…发落
    If you throw yourself on someone's mercy, you put yourself in a situation where they will have complete power to decide how to treat you, for example whether to punish or forgive you.

    e.g. He's going to throw himself on the mercy of the court.
           他准备听凭法庭发落。