Dictionary.net

A seller's taking advantage of a buyer due to their unequal bargaining positions, perhaps because of the buyer's recent trauma, physical infirmity, ignorance, inability to read or inability to understand the language. The unfairness must be so severe that it is shocking to the average person. It usually includes the absence of any meaningful choice on the part of the buyer and contract terms so one-sided that they unreasonably favor the seller. A contract will be terminated if the buyer can prove unconscionability.