Sentence:  If one believes that morality plays no part in such a transaction, and that the law is all that prevails, then I believe society is the poorer. Clearly no surveyor refuses to act for a client who <WSD>gazumps</WSD> — but while the practice is legal it can hardly be described as moral, and the position of the surveyor is far from clear. 
Meaning of the word marked with <WSD> tags:  To raise the selling price of something (especially property) after previously agreeing to a lower one.