1. To raise the price of a house after a certain price has been agreed-upon but before the sale has been finalized. The deal fell apart when the seller gazumphed the price of the house.
2. To impact someone else by raising the price of a house in this manner. We're a little wary after getting gazumphed the last time we put in an offer.
1. tv. to raise the price of a house after it is sold. They tried to gazumph the price at the closing.
2. tv. to subject someone to the raising of the price of a house after it is sold. If they try to gazumph you, tell them to forget the deal.