The underground market is commonly known as a black market or shadow economy. It is the place where illegal goods, such as drugs, firearms, and contraband, are traded without government approval. Other synonyms for the underground market include the illicit market, hidden economy, gray market, and clandestine marketplace. The underground market can operate online or offline, and it thrives in countries where there are strict regulations or high taxes on certain goods. The black market can be dangerous, as criminals may use it to distribute dangerous and counterfeit products. Despite the potential risks, the underground market continues to exist as people seek to evade government oversight and taxes.