1. 勒索；敲诈；讹诈
    Blackmail is the action of threatening to reveal a secret about someone, unless they do something you tell them to do, such as giving you money.

    e.g. It looks like the pictures were being used for blackmail...
           这些照片好像被用于敲诈勒索。
    e.g. Opponents accused him of blackmail and extortion.
           对方指控他敲诈勒索。

2. （情感或道德上的）迫使，胁迫
    If you describe an action as emotional or moral blackmail, you disapprove of it because someone is using a person's emotions or moral values to persuade them to do something against their will.

blackmail的意思

    e.g. The tactics employed can range from overt bullying to subtle emotional blackmail.
           从公然威吓到微妙的情感胁迫，各种战术都用上了。

3. 勒索；敲诈；讹诈
    If one person blackmails another person, they use blackmail against them.

    e.g. He told her their affair would have to stop, because Jack Smith was blackmailing him...
           他告诉她说他们的婚外情必须结束了，因为杰克·史密斯正在敲诈他。
    e.g. The government insisted that it would not be blackmailed by violence...
           政府坚持说它不会接受暴力讹诈。