Wisdom is a prominent theme in several Biblical books, but what is it? Wisdom is often confused with knowledge and understanding, but they are not the same thing. While knowledge represents familiarity with facts, and understanding has to do with grasping meaning, wisdom has to do with the practical application of what one knows and understands. In other words, you can memorize and "get" everything in the encyclopedia, but if you just stand there drooling once you have it all, you're not showing any wisdom.
To that extent, wisdom also has a great deal to do with morality. Proper application of knowledge and understanding (e.g., wisdom) leads to good moral decisions, as is implicit in the message of books like Proverbs and Sirach. Knowledge and understanding by themselves are neutral -- it is only when it is used one way or the other than some aspect of wisdom comes into play.