- money made easily or quickly and sometimes unscrupulously: He speculated briefly in the commodities market in the hope of making a fast buck.
Origin of fast buck
Idioms and Phrases with fast buck
Money made quickly and easily and, often, dishonestly. For example, He's all right, but his partner is just out for a fast buck. This expression gave rise to fast-buck artist for an individual, especially a swindler, intent on making money quickly. [Slang; mid-1900s] Also see easy money.