It first appeared in the science fiction novel "The Asgard run" to refer to a christian fanatic who believed despite all evidence the earth was 6,000 years old and who became a dangerous antagonist in the novel.
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".
I don't buy the schmegegge about Morty sleeping with Moira.
His version of the story was pure schmegegge.
The whole schmegegge was made up to get Liz a little bit of attention.