Am I an atheist? Or an agnostic? (Or something else perhaps…)
I) Trivially: atheism1 means "an absence of theism", and nothing more.
That is the complete and entire definition of the word. (If not quite it's informally understood nor accepted meanings)
Colloquially: an atheist is a person who lacks belief in any deity.
(The word "belief" is quite germane to this definition)
"atheism" is composed from the Greek prefix "a", meaning lack of, or absence of, and "theism", (Greek for the belief in at least one deity.2)
As such, I shall occasionally write it as "a-theism", in a feeble attempt at didacticism.3
So, in the trivial sense at least, mineral rocks are atheist, as they lack a belief in deities.
Newborns infants are atheists for the same reason: they lack the ability to believe in deities.4
Human atheists are often sub-categorised as those folk who are actually capable of expressing their active & intentional percieved lack of theism.
(As opposed to say, a planarian worm, or a mushroom, which are not capable of expressing a lack of theism; despite what hippies, or scientists, may feel.)
It is important to note that this category is a sub-set of atheists, and of atheism, as an attempt to remove the "trivial" aspect.
What is certain is that the traditional dictionary definitions of atheism are in serious and egregious error, at least those that claim that atheism is an explicitly deliberate and conscious rejection of the non-existent especial personal god of the lexicographer.
The arch-Christian Noah Webster was famous for this monstrously ignorant injustice.
(For he was an atheist with respect to Minerva, or even Sol)
In other words: This definition is quite superior to that of most dictionary compilers! ;)6
II) Atheism and agnosticism.
Theism and a-theism are all about BELIEF.
Remember that word. It is vital to the understanding of what atheism is NOT about.
You know the term "agnostic"?
This is a neologism coined5 to reflect a lack of "gnosticism", which is a name for a state of mind in which one supposedly KNOWS (as opposed to 'has a belief') about deities, via some otherwise unmanifest source that the gnostic invariably labels 'revelation', without further coherent explanation of what they mean by the word.
'Gnosis' is Greek for 'Knowledge'. (There was a very cleverly named record label called "Hipgnosis" in the 70's:- "Knowledge of Coolness")
So: anosticism/gnostism is about acquired KNOWLEDGE from some putative entirely external source.
And atheism/theism is about BELIEF which need only be sourced from internal personal emotion, or from an organic brain disorder, (such as schizophrenia) but may also be sourced from infant indoctrination, and so-on.
Now we are getting somewhere!
Colloquially: an agnostic is a person who entirely lacks supposedly externally sourced knowledge about any deities.
Let's plot than on a Cartesian graph, with wherein I consider various candidates to lay, (and lie in many cases!):

As you can see, atheism and agnosticism are quite independent of each other.
They refer to different ideas.
Agnostic is most certainly not a weak form of "atheistic", for the two address entirely orthogonal concepts.
One can be any combination of the two, across both of their spectra: Wholly atheist through to Entirely theist on the one axis, combined with Entirely gnostic through to Totally agnostic on the other axis.
This spectrum is now a 2-dimensional 'area', where one is (say) 98% atheist and 5% gnostic.
Pin the tail on the donkey! Or pin the tail on the Gnostic/Theist graph. Upon which coordinate do you lay?
Am I an Atheist?
So, to know whether or not you are an atheist, ask yourself the following:
Do I sincerely believe in a deity, or deities?
If the answer is not a confident YES, then you are an atheist. That applies even if the answer is "I'm not really sure".
Notes
Theism is often compared to parasitic infections, especially viruses.
Not an infection by a physical agent, but by another reproducing entity called a 'meme'.
Loosely put, a meme is a self-reproducing set of behaviours, such as a catchy tune, or even one that has co-opted the term: an
internet meme.
Habits & Religious Rituals fall into this category. Note that the habit does NOT have to benefit the person doing it! (Think nail-biting, starving rather than eating pork, obsessive ritual hygiene, or celibacy.)
Too many otherwise educated folk assume that because humans possess a trait, it ipso facto MUST have a beneficial purpose in evolutionary terms, so they hunt around for a reason why say ritual celibacy must have been good for the host of this meme.
And it is at this point they earn an EPIC FAIL stamp.
Yes, it does confer an evolutionary advantage for these memes to survive, but NOT for the host. The survival advantage belongs to the reproducing entity, (in the case of monastic celibacy the reproducing entity is the religious meme), not the monk. Any benefits for the host are either incidental (at no direct cost to the meme's reproduction), or essential for the meme to reproduce.
For clarity's7 sake, I shall refer to the person/monk/nun/credulous
believer as the 'host', and the reproducing entity as the "parasite".
SO, a religious ritual may well be lethal for the host, as long as the host has a good chance of passing on the parasite to another entity, the parasite will survive, and doesn't give a tinker's cuss about the host!
Incidentally, the meme does not have to be passed on immediately. It may lay dormant for millennia before being passed on.
The Dead Sea Scrolls, the Egyptian "Book of the Dead" come to mind as popular examples.
There are many fascinating publications on this subject, should you wish to pursue it further.
(Blackmore, Dennett, Dawkins, Pinker etc)
Common mis-spellings:
- atehism
LOLcat style? - athiest
I am athier than thou!
The nominal neo-declensions are therefore: athie (or athy), athier, athiest.
Common Errors
Theist apologists have what seems a favourite 'tactic' of conflating the concepts of
- faith
- belief
- confidence
- trust
- knowledge
And then exploiting that false conflation for their evil purposes!
An especial fave of these liars is to claim that 3. (trust) is the same as 1. (faith), as in:
"You believe that protons are made of quarks, don't you? On the say-so of your scientifical priests alone!"
No, we don't 'believe" that in any mystical sense. We TRUST the overwhelming evidence of the scientific method, and its built-in self-correcting nature.
As diametrically opposed to faiths of all kinds, where internal self-correction is restricted to the purely cosmetic, (referring to rival churches as 'colleagues' instead of 'enemies'), and the essential to ensure the meme's survival in the face of the social zeitgeist, (biblically mandated slavery, or the obligatory mandate to publically murder insolent offspring to name but a few).
Notes:
1 No capital letter please
2 Pedantic classics scholars will object, and have objected, that it is a little more subtle than that, but that will do for a brief definition.
Ancient Greek is difficult to directly translate at the best of times, and words such as 'logos' are notoriously shape-changing.
"Theos" is another slippery customer. In many cases is meant just "belief". That there were real gods was axiomatic. So, for most ancient Greeks, one either believed in individual deities or not, but they still existed. Much as one can choose to believe in gravity or not. Those who don't believe in a god wouldn't make it go away. It just made the unbeliever seem a trifle strange. (And possibly a Foreigner!! Horror of Horrors for an ancient Greek.)
This ancient notion (theism=belief) is actually closer to the heart of the theism/atheism debate than many others, for it neatly encapsulates the core concept of 'belief' into theism.
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3 Ed: Shouldn't that read "paradidacticism"? Never mind!
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4 No smarty-pants comments that they think that their mother is a deity of some sort!
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5 By Thomas Huxley, Gent., "Darwin's Bulldog"
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6 It *is*, so THERE!! Nya!
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7 Niels Bohr, when asked in German about Heisenberg's famous 'Conjugate Complementarity Principle' (that say, speed & position are complementary, and gaining more precision in one neccessarily entails less precision in the other and vice versa):
Paraphrasing: "What is complementary to Wahrheit?" (truth) — He rather pithilly rhymed: "Klarheit
" (clarity), and that definitely applies to these definitions/explanations of meanings!
The shorter is the explanation, the less accurately it reflects reality, and the closer to reality it approaches, the lengthier & less clear it becomes. Sigh…
It appears to be a condensed version of his favourite couplet by Schiller:
Nur die Fülle führt zur Klarheit. Und im Abgrund wohnt die Wahrheit.
(1994 Niels Bohr and contemporary philosophy By Jan Faye, Henry J. Folse, pp 150,151)

Comments
Atheist or agnostic?
A very good article, marred by: (1) a misunderstanding of the way evolution works. (It is GROUP survival which counts, not individual survival, so a few celibate monks may provide an evolutionary advantage to the larger group.) (2) assuming that Dawkins's "memes" have been accepted into the scietific literature. (A nice idea, but untested, probably untestable.)
Group Survival?
Firstly, I accept that both I, and Dawkins may well be incorrect.
1) Group survival has been almost entirely demolished by the gene survival paradigm, as far as I can determine.
Dawkins has admitted to a very, very limited form of group selection, (but not group survival.)
No evolutionary biologist has been able to support the robust concept, unless I am mistaken, and I include S.J. Gould in that category.
Celibate Monks provide a distinct evolutionary advantage to the meme, that much is abundantly clear.
What do you mean (exactly) by your assertion that they proffer an advantage to "the larger group"?
What "larger group"?
What "advantage"?
I await your input on this point with scholarly anticipation.
Are you able to support the concept of group selection?
If you are, I shall put your response to Dawkins as I intend meeting him on the 1st of March.
I am sure that he would be vitally interested in your input supporting group selection. Seriously.
2) "Dawkins' memes" concept have been accepted with considerable gusto into the scientific literature. Blackmore, Dennet, Pinker etc.
It is hardly 'untestable', and has been tested many times, as far as I recall.
I shall appreciate your forthcoming corrections to my blunders.
Replete with both evidence and references, please. If I am to learn, I wish to be shown not only that I am wrong, but exactly why.
I trust that you will excuse my apparent 'shortness' with you, but you may take solace that I mean no ill, and that my brevity is entirely my own shortcoming, not yours.