1. 与上帝（或宗教）有关的;神圣的
    If you describe something as holy, you mean that it is considered to be special because it is connected with God or a particular religion.

    e.g. To them, as to all Christians, this is a holy place.
           对他们以及所有基督徒来说，这里是一处圣地。
    e.g. ...Yom Kippur, the holiest day in the Jewish calendar.
           赎罪日，犹太历中最神圣的日子

2. 虔诚的;圣洁的;献身于宗教（或教会）的
    A holy person is a religious leader or someone who leads a religious life.

holy的解释

    e.g. The Indians think of him as a holy man, a combination of doctor and priest.
           印度人把他视为圣人，他既是医生又是僧侣。

3. （表示惊讶、恐慌等）天啊，上帝啊
    Holy is used in exclamations such as 'Holy cow!' and 'Holy smoke!' to express an emotion such as surprise or panic.

4. see also: holier-than-thou