1. 防御;保卫;保护
    If you defend someone or something, you take action in order to protect them.

    e.g. Every man who could fight was now committed to defend the ridge...
           每个能够参加战斗的男子现在都决心要保卫这条山脊。
    e.g. His courage in defending religious and civil rights inspired many outside the church...
           他在捍卫宗教和公民权利时所表现出来的勇气鼓舞了许多教会之外的人。

2. 替…辩护;为…辩解;维护
    If you defend someone or something when they have been criticized, you argue in support of them.

    e.g. Matt defended all of Clarence's decisions, right or wrong...
           克拉伦斯的决定，不管对错，马特都予以维护。
    e.g. The author defends herself against charges of racism by noting that blacks are only one of her targets...
           面对种族主义指控，作者替自己辩护说黑人只是她的抨击目标之一。

3. (律师)为(被告)辩护
    When a lawyer defends a person who has been accused of something, the lawyer argues on their behalf in a court of law that the charges are not true.

    e.g. ...a lawyer who defended political prisoners during the military regime...
           在军人政权时期为政治犯辩护的律师
    e.g. He has hired a lawyer to defend him against the allegations...
           他已聘请了一位律师针对这些指控为自己辩护。

4. 卫(冕)
    When a sports player plays in the tournament which they won the previous time it was held, you can say that they are defending their title.

    e.g. Torrence expects to defend her title successfully in the next Olympics...
           托伦斯希望在下届奥运会上能够卫冕成功。
    e.g. India had to struggle to beat defending champions South Korea 2-0.
           印度队苦战之下才以 2 比 0 击败卫冕冠军韩国队。