Originally, “shrew” referred to the small burrowing animal with very sharp teeth. The animal’s name derived from the German “skreu-”, to cut. Because shrews are ferocious and their bite is poisonous, it was believed that they were possessed by an evil spirit. So when the word was first applied to people, it referred to an evil person, a devil. By Shakespeare’s time though, the meaning had mellowed and narrowed. It referred specifically to a scolding, ill-tempered woman. A woman behaving in this manner was described as shrewd. Today, the noun, shrew, is rarely heard, but when it is, it has the same meaning as in Shakespeare’s day. However the adjective, shrewd, has taken on a very different sense. In the very early times when “shrew” still referred to a devilish person, to be shrewd meant to be very cunning at performing evil deeds. Ironically, today it’s generally used in a positive sense, to describe someone who’s very savvy or clever.