It was coined in the Elizabethan Era to describe women as having big boobies and always being horny and wanting the awooga with everyone they meet. Essentially someone called a watercake was branded a hoe.
"oh look at that watercake she's at it again with Jerry from next door"
"the watercakes of this city are going round to everyone.
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".