The Gemora (Bava Kamma 83) states that Greek wisdom is not the Greek language, but does not explain what Greek Wisdom is. This is, of course, extremely relevant, as the braisa stated that one who teaches his son Greek Wisdom is cursed. The Shitah quotes a Gaon who says that Greek wisdom is a form of communicating in hints, without all people understanding the content (similar to the Oracles of Greek history). This fits well with the story the Gemora quoted (82b), in which an old man communicated important information to the army outside of Yerushalayim, which led to the curse. The Shitah quotes the Rema who says that Greek wisdom is predicting the future based on astrology. The Meiri says that Greek wisdom is Greek philosophy, which was forbidden due to its tendency to attract people and draw them away from many fundamental religious principles. Those who had to interact with the royalty needed to be versed in these areas, in order to be socially acceptable to the royal mileui.