One who sits in class oblivious to his or her surroundings, perhaps those that are occurring outsidea window.
Megan sat in her desk staring blankly at her test without noticing the illicit cheating that was going on around her as well as the screaminggoing on in the hallway, like a nerdroid.
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".