1. （常指逐渐或反复）削弱，损害（情感、体制等）
    If you undermine something such as a feeling or a system, you make it less strong or less secure than it was before, often by a gradual process or by repeated efforts.

    e.g. Offering advice on each and every problem will undermine her feeling of being adult...
           对每个问题都给出建议会令她觉得自己不像个成年人。
    e.g. Western intelligence agencies are accused of trying to undermine the government.
           西方情报机构被指责企图动摇该政府的统治。

2. （常指间接地）削弱，损害，动摇（某人的地位或权威）
    If you undermine someone or undermine their position or authority, you make their authority or position less secure, often by indirect methods.

    e.g. She undermined him and destroyed his confidence in his own talent...
           她暗中打击他，让他对自己的才华信心全无。
    e.g. The conversations were designed to undermine her authority so she felt that she could no longer work for the company.
           这些谈话有意削弱她的威信，这样她会觉得自己在公司干不下去。

3. 破坏，损害（某人的努力或成功的机会）
    If you undermine someone's efforts or undermine their chances of achieving something, you behave in a way that makes them less likely to succeed.

undermine在线翻译

    e.g. The continued fighting threatens to undermine efforts to negotiate an agreement...
           持续的战斗会破坏希望通过谈判来达成协议的努力。
    e.g. I don't want to do something that would undermine the chances of success.
           我不想做会影响成功机会的事情。