To unfairly raise the agreed price of a property after a deal has been made, or to accept a higher offer from a third party.

Origin: The term 'gazump' originated in the 1920s, likely deriving from the Yiddish word 'gezumph', which means to cheat or swindle. This Yiddish term itself possibly stems from the Hebrew word 'gezell', meaning theft or robbery.Historical and Cultural Context: The word was first used in the context of real estate in Britain, during a time when property transactions were becoming more common and competitive. It encapsulated the practices of unscrupulous sellers who would increase the price of property after a verbal agreement had been made with a buyer.Evolution: Over time, 'gazump' has retained its original meaning but has also come to describe similar practices in other types of transactions, such as during auctions or in the stock market. It is closely related to terms like 'gazunder', which refers to lowering an offer price at the last minute.Modern Relevance: Today, 'gazump' is commonly used in the UK and Australia in the context of real estate and other negotiations, especially when describing unethical practices during transactions.

The term 'gazump' was popularized in the UK during the post-World War II housing boom, highlighting the cutthroat nature of the real estate market at the time.