Definitions of gazump
to make a higher offer for a property (eg a flat or a house) than someone whose offer has already been accepted by the seller, and because of this higher offer to succeed in buying the property. In some jurisdictions, this is possible. However, other jurisdictions have passed legislation making offers on houses binding at an earlier stage during the process of buying a property.
In 2002, the Yorkshire Bank reported that one in ten UK home buyers was prepared to gazump to secure a house purchase.