1.The opposite of legitimate business. 2.A street hustle, or a shady and mostly illegal business venture.
3. Dealings that aren't exactly "street legal"
Bloomingdales=Business. Selling dresses and purses out of your trunk=Bidness
The word used to substitute the "business" when not meant to be used in its literal context. Often used in the context of "None of your business" without trying to sound too white.
Proper use of the word "bidness":
Yeah, my pops owns a business, but it ain't nunyo damn BIDNESS, ho.