I am a theist, what do you think of my proof for God existing?

[Astreja]

Okay, you win.  I will come up with a "concept of God" in 30 words or less.

A mythological Jewish deity appropriated by Christianity, Islam and, most recently, Wicca created by primitive people with a desire to explain the world around them but without the intellectual means to do so.

Okay, it's 33 words.

As a polyatheist, I'd define it as:

Hypothetical sentient entity capable of creating universes without leaving any evidence whatsoever for its existence.