"FU Money" represents the amount required for a person to stop being employed. FU is way of, er .. saying "goodbye" to your employer. U the FU stands for You and the F stands for one of the most popular expletives 🙂 A person is then free to follow her passion and wait for it to generate an income without having to worry about expenses for at least a few years. Or the corpus could be large enough to generate an inflation-protected income for the rest of her life.