But assuming you are not agnostic, then you believe there is no god. So you do not have an absence of faith, you have faith in an absence that (IMHO) cannot be proven either way.
Just because something cannot be proven, does not mean it is false. Trees falling in a forest with nobody around, etc., etc.
In philosophical circles, and where people haven't been raised listening to annoying people repeatedly shout that "atheists are all evil militants", the definitions of agnosticism and atheism aren't exclusive. They're:
atheism: I don't believe in the existence of gods
agnosticism: I believe the existence or non-existence of gods to be fundamentally unknowable
You can be an agnostic theist or an agnostic atheist. There's no overlap, atheism and agnosticism are answers to completely different questions; atheism answers "do you believe in gods", agnosticism answers "do you believe that the existence or non-existence of gods is knowable". Notice that "atheist" doesn't mean "I know with certainty that God doesn't exist". That's a subset of atheism we often call "strong atheism", but it's just a subset. So you see, there's no "faith" here. Atheism just means "I have no belief in gods", nothing more, nothing less.
There is another definition of agnosticism and atheism, that is:
Statement: God(s) exist.
Atheist (other): false (with certainty)
Agnostic (other): unknown
Theist (other): true (with certainty)
The problem with this is that we cannot, rationally, consider the existence of anything for which we have no evidence to be false with 100% certainty. Nothing. So you're agnostic towards gods; you're also agnostic towards unicorns, leprechauns, Reptilian Obama, invisible teapots, and so forth, because that's the only rational course. This is a silly way of looking at things, however. You can't live life as though unicorns might exist, just because you don't have any evidence against them. So instead we use the other question: do you have belief in gods? As in: do you consider "gods exist" to be true? Using the other definitions again:
Atheist: no
Agnostic A: no
Agnostic B: Uncertain
Agnostic C: yes
Theist: yes
Okay, you've agnostic groups A and C can be merged in with our normal Atheist/Theist definitions, leaving us back where we were, but with a third category:
Do you have a belief in gods?
Atheist: no
Agnostic (type 2): uncertain
Theist: yes
It happens, it can happen with any belief, but it's shaky ground. In this state, you are considering theism to be potentially plausible. If you're doing this without evidence, this is an irrational state, make no doubt.
Short: atheism means "no belief in gods", not "I believe there are no gods". Agnosticism either means "belief in gods is unknowable" or "existence of gods is unknown" or "I'm uncertain where I believe in gods". The first two aren't incompatible with theism or atheism. The third is a shaky middle ground where one is not atheist, not fully theist, but still seems to be swayed by theism for some reason, which may be as irrational a position as theism.