Is atheism a belief?

[The Grand Nudger]

I certainly agree with you that there is no coherent definition in the Bible. That's why sola scripture literalists don't interest me. 

The different definitions given later, on the other hand, have been pretty interesting. Always with the caveat that just about any definition accepts an apophatic element -- something as beyond human understanding as god cannot be described completely in human terms, they say.

Right off the bat, the definers insist that they are meaningfully wrong.  Great start. 

Anyway, Nicholas of Cusa, in line with his mathematical work, defined god as infinite and completely immanent, which allowed him to propose a non-geocentric universe decades before Galileo -- and he didn't even get in trouble.

This one was a head scratcher.  What could that description of a god concept have to do with the proposal of a non-geocentric universe, I wondered?  So I googled the guy.  Turns out his socioeconomic status as the educated son of prosperous parents who became a papal envoy and was then elevated to cardinal is what allowed him to do that and not get in trouble.  So, not only can I reject that wishy washy definition for an existent god out of hand, I can also reject your characterization of it and what ought to impress me about it. 

 Jacob Boehme defined god as a dialectic of spirit, unfolding entirely through human beings, a concept which Hegel called the foundation of modern thought.

Hegels characterization of modern thought, hegel, circa 1770-1830ish...? It refers to something that was significantly flawed, itself, and which lends no credence to any definition of a god in the first place.  This, again, and the reason it ought to impress..can be rejected out of hand like the first.

I'm certainly not arguing that either of these definitions is persuasive. I'm not saying you should study them or value them at all. 

What's important, to me, if we genuinely propose that their ideas should be rejected, is that it requires better reasons than the old Sky-Daddy concept does. Of course a person could reject those ideas on a whim, or because he just doesn't like the word "god." But I don't think those would be good, thought-out reasons. They're no better than a fundie who rejects evolution because he doesn't like the sound of it. 

Anyone atheist who rejects all concepts of god for the same reasons he had as an infant is thinking at an infant's level, and hasn't thought out his conclusions.

They can all be rejected out of hand for attempting to manufacture a referent rather than describe one.  It might have been more helpful to point out something about the definitions themselves, rather than attaching some tertiary claim, if we wanted a more thorough perusal of the ideas and how the contents can be rejected simply or significantly.  Here;s the rub, though.  If you can reject something simply, for a base reason..it doesn't matter how visciously you approach the flourish and baubbles in the larger concept.  

If someone told you that there were dragons of indescribable finery, you could reject the notion of indescribable finery as an incoherent concept of propositional accuracy under this or that theory of language - or you could just remind the guy that they are no dragons to be indescribably fine in the first place.  It doesn't matter how fine or how plain a person asserts them to be. Similarly, the ultimate problem of specific god definitions is not their relative finery, complexity, or flourish.

That's not the focus of atheism, nor what atheism rejects. Atheism rejects the base existential claim, not the finery, complexity, or flourish of a definition or that it can effect the world. As an atheist, this is the only thing required to reject any description of a god.