A term intended to mock the use of or explanations containing the term "economy" - or any related term - by those who know little or nothing whatsoever about the actual functioning of domestic or global economic systems.
The "Mc" generally recalls other common terms to which the prefix has been added in order to diminish their intended meaning (i.e. "McMansion").
I found it hilarious when our science professor launched into a diatribe about when we would recover from the current economic crisis. He kept saying, "well, you know, the McConomy is what it is, it has its ups and downs, you know?"
"It really all comes down to the McConomy."
"Well, I bet it's pretty hard to go out and find a job right now, given the current McConomy and all."