Sentence:  During the early 1970s however in a period of rapidly increasing house prices it came to appear unfavourable to buyers since it allowed the seller to ‘<WSD>gazump</WSD>', that is to refuse to sign the formal contract unless the buyer would agree to an increased price. 
Meaning of the word marked with <WSD> tags:  To raise the selling price of something (especially property) after previously agreeing to a lower one.