This simply means a beautiful young single lady with a fair or light skin. But since now-a-days that seems to be a racist insinuation the meaning shifted to simply imply a lady with good characteristic and qualities.
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.