The best way to understand the nature of atheism is to understand its author. satan is its author.

It's important to remain conscious of the fact that satan had his origin in heaven, and is thoroughly familiar with the fact of the existence of God, heaven, the angels, hell and etc. Thus despite what you have been previously deceptively taught and despite the deceptive dictionary's meaning of atheism, atheism is properly defined as a denial of the existence of God in the midst of full knowledge that the true God does indeed exist. (Emphasis original).