1. (言行)谨慎的，考虑周到的
    If you are discreet, you are polite and careful in what you do or say, because you want to avoid embarrassing or offending someone.

    e.g. They were gossipy and not always discreet...
           他们很爱传闲话，而且常常口无遮拦。
    e.g. He followed at a discreet distance.
           他小心翼翼地尾随在后，保持着一段距离。

2. 言语谨慎的
    If you are discreet about something you are doing, you do not tell other people about it, in order to avoid being embarrassed or to gain an advantage.

    e.g. We were very discreet about the romance...
           我们对这段恋情很谨慎。
    e.g. She's making a few discreet inquiries with her mother's friends.
           她旁敲侧击地向她母亲的朋友们打听过几次。

3. 不显眼的;朴素的;少的;小的
    If you describe something as discreet, you approve of it because it is small in size or degree, or not easily noticed.

    e.g. She wore discreet jewellery.
           她戴着素净的首饰。