A person who has a one-track mind, one that spins in circles, generally on a single, annoying topic without ever really making a valid or substantial point.
Our President is a complete hamsterhead when it comes to his fixation on insulting the appearance or mannerisms of members of the media who are critical of his ineptitude.
Someone who is addicted to obtaining money and building wealth. A money addict and fanatic. Breadheads often work more than one full-time job, and some even participate in illicit activities to "obtain the bread".