gazunderga‧zun‧der /ɡəˈzʌndə $ -ər/ verb [transitive] British English informalWord Origin
WORD ORIGINgazunder
Origin:
1900-2000 Probably from gazump + under
be gazundered if you are gazundered, someone who has agreed to buy your house says that they will only buy it for less than the amount originally agreed