I am technical an atheist; However an atheist is not something that you so much are. Rather, it's something you are from a theistic perspective. Ultimately the word only says what you're not, that the term "theist" is not applicable to you. It is a negative label; I don't wish to label myself negatively. Even theists themselves are atheists in regards to other religions, hence the term atheist applies to both, making the term meaningless.
An atheist has no belief I repeat that no believe in god/gods, he also has no belief in fairies and elves etc. That’s not to say that any of those things couldn't exist, it is just simply unreasonable to have a belief in such things, atheist's simply lack belief.
Atheists do not invoke any concept of god to explain any phenomenon or solve any philosophical conundrum, and they see no compelling reason to.
Atheist do not profess to have the truth, it is simply that it is unreasonable, without further qualifying evidence.
An atheist is simply someone who does not posit a god-concept to explain anything or solve any problem, it is not mutually exclusive with agnostic. You can be agnostic with respect to some god-concepts while maintaining an atheistic nature toward them all.
It would be extremely foolish to say they believe god doesn't exist, the non-existence of a thing can never be conclusively proved because there is always the theoretical assumption that the thing exists but has not been seen yet or it exists in a place that cannot be visited. Unless all places in the universe have been visited and are being constantly observed, we cannot be absolutely certain.
Atheist is simply "without god(s)" from the Greek origin of the word. The same way asexual is "without sex" and amoral is "without moral(s)." The same way achromatic is "without colour" and aphasia is "without ability to express or understand language."
The following definition of Atheism was given to the Supreme Court of the United States in the case of Murray v. Curlett, 374 U.S. 203, 83 S. Ct. 1560, 10 L.Ed.2d (MD, 1963).
"An Atheist loves his fellow man instead of god. An Atheist believes that heaven is something for which we should work for now – here on earth for all men together to enjoy.
An Atheist believes that he can get no help through prayer but that he must find in himself the inner conviction, and strength to meet life, to grapple with it, to subdue it and enjoy it.
An Atheist believes that only in the knowledge of himself and the knowledge of his fellow man can he find the understanding that will help to a life of fulfilment.
He seeks to know himself and his fellow man rather than to know a god. An Atheist believes that a hospital should be built instead of a church. An Atheist believes that a deed must be done instead of a prayer said. An Atheist strives for involvement in life and not escape into death. He wants disease conquered, poverty vanquished, war eliminated. He wants man to understand and love man.
He wants an ethical way of life. He believes that we cannot rely on a god or channel action into prayer nor hope for an end of troubles in a hereafter.
He believes that we are our brother's keepers; and are keepers of our own lives; that we are responsible persons and the job is here and the time is now.”
So to sum it up an atheist is a morally better person, than any theist could aspire to be. The atheist does good things simply because it is the right thing to do, and simply for the betterment of his fellow man.
The one, true definition of 'Atheist' is 'without belief'.
The "A" prefix means without/non/aint got no.
Asexual=having no sex or sexual organs.(not a belief there’s no sex organs)
Amoral=without moral.(not a belief there’s no morals)
Apolitical=not political.(not a belief there’s no politics)
Atypical=not typical.(not a belief there not typical)
Asymmetric=not symmetrical.(not a belief there’s no symmetry)
Atheist=not theist.(not a belief there’s no god) that’s IT. No other assumptions can be made from it.
Incidentally, I label myself as a Humanist.