Underground economy is a term that defines those individuals and businesses that deal with cash or use other schemes to hide their activities and their  tax liability from government licensing, regulatory, and taxing agencies. The part of a country's economic activity that is unrecorded and untaxed by the government. The underground economy can be beneficial can be characterized as "Black Market" which goods and services are bought illegally. For example, the selling of drugs on streets or buying untaxed cigarettes and alcohol. Not many people think of illegal street vendors or unlicensed businesses as a contributor to our economy. In some ways they are beneficial. Such as adding jobs, increasing sales, and improving the lives of hundreds of humans. In other ways the hidden economy can be seen as detrimental. All the economic activity basically "flies under the radar of government". Unregistered, unregulated, untaxed, but not criminal. I hate guns.