Sentence:  Here's a Humbugger come, / Will prove the reſt nothing at all, / 'Tis a Jobber, a Factor, / A damn'd Corn Contractor, / Who makes all our Loaves be ſo ſmall; ... And may all ſuch elves, / Be thus <WSD>Humbugg'd</WSD> themſelves, / Who thus are <WSD>Humbugging</WSD> the poor: / And as ſure as the Bone makes the Cleaver to ſound, / <WSD>Humbugging</WSD>, <WSD>Humbugging</WSD> goes all the world round. 
Meaning of the word marked with <WSD> tags:  To play a trick on someone, to cheat, to swindle, to deceive.