An individual owner of a small, start-up business who is, in the end, totally full of shit; a new business owner who lacks experience in management, marketing, accounting, etc.; a business owner who develops or markets a "new" product that is utterly useless, ridiculous, or just plain stupid. Variations include "entremanurial" (adj.), entremanurism (n.)
I'd like you to meet Rob, who sells edible undies that taste like broccoli. He's a real up-and-coming entremanure.
My client, who opened a Victoria's Secret store in Islamabad, definitely has the 21st century entremanurial spirit.