英汉词典

1. 偶然听到；无意中听到；偷听到
    If you overhear someone, you hear what they are saying when they are not talking to you and they do not know that you are listening.

    e.g. I overheard two doctors discussing my case.
           我无意中听到两位医生讨论我的病情。
    e.g. ...snatches of overheard conversation.
           偷听到的片言只语