A repugnant market is an area of commerce that is considered by society to be outside of the range of market transactions and that bringing this area into the realm of a market would be inherently immoral or uncaring. For example, many people consider a market in human organs to be a repugnant market or the ability to bet on terrorist acts in prediction market to be repugnant. Others consider the lack of such markets to be even more immoral and uncaring, as trade bans (e.g. in organ transplants and terrorism information) can create avoidable human suffering.

Nobel Laureate Alvin Roth (2007) "introduced in the economics literature the concept of “repugnance” for a transaction as the aversion toward other individuals engaging in it, even if the parties directly involved benefit from that trade (i.e. “There are some things no one should be allowed to do”). Repugnance considerations have important consequences on the types of markets and transactions that we observe and, as such, they impose a challenge for policy and market design."