Atheism, by definition, is the belief in the non-existence of any deity. I am non-religious, but no sir, I am not an atheist. I believe there is something more to life then what we can possibly come close to understanding through science or religion. If you cannot truly believe(<—key word there) that there is no deity at all, then you will have to fess up and admit that you are an agnostic, not an atheist. But then you would have to change up this website and that would take up too much time.
I disagree. Atheism is, by definition, the non-belief in a deity. Some atheists assert the non-existence of any deity, but not all of them. I do not.
An agnostic is someone who believes that it is in principle impossible to prove or disprove the existence of a deity. I believe that if a deity exists, it might be possible to prove to me that it exists. Therefore I am not an agnostic; I am an atheist.