...then you would have to justify that definition before expecting anyone to accept, prove, or disprove it.
FWIW I was once a believer and frequently associate with believers, so I have some experience in the matter and have given it considerable thought.
The point is I'm not talking about a specific God or assuming anything about the nature of God like many religions do. Once you remove all that baggage God is just a term that means "the thing that created the universe." So to deny the existence of God you must deny that the universe was created by something. I don't see how you can make such a claim without any evidence. Last I checked there was no scientific explanation for the creation of the universe.
It's an unnecessary complication; if calling the Big Bang or whatever might have preceded it "god" provides useful explanatory and predictive power, then such a definition might gain some traction. But as it is, the universe appears indistinguishable from a naturalistic physical process.