1. 给…通风报信;暗中告知
    If someone tips you off, they give you information about something that has happened or is going to happen.

    e.g. Greg tipped police off on his car phone about a suspect drunk driver...
           格雷格用他的汽车电话向警方报告了一个有酒后驾驶嫌疑的司机。
    e.g. He was arrested two days later after a friend tipped off the FBI.
           他的一个朋友给美国联邦调查局报了信两天以后他就被捕了。

verb

1. give insider information or advise to

    e.g. He tipped off the police about the terrorist plot

    Synonym: tip