When a person embezzles, it usually means that he is stealing money from his employer. If he is caught embezzling, it probably also means that he will soon be unemployed.
The word embezzle implies more than simply "to steal." When a person embezzles, he or she takes advantage of an employer's trust for personal gain. Embezzling is a so-called "white-collar crime" which often involves some sort of cover-up, like falsifying financial records or stealing small amounts of money over a long period of time. The word embezzle comes from an Old French word meaning "maltreat or ravage," besillier, and an embezzler can be said to ravage someone else's money.