When you call someone this you are essentially calling them gay. You're saying that they partake in butt sex. If you take the word apart, then it will make since: deuce on man dick. It's written together because you say it as one word.
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".