No, it isn't.
Not believing in the existence of a God (or gods) is what makes someone an atheist. Rejecting, defying, and ignoring sound far too much like activities that at least require belief.
eudaimonia,
Mark
One of the issues I have with the single, individual atheist, is similar to an issue I have with the believer ... their definition of "god".
A believer can claim to believe in a "god", and an atheist can claim to lack belief in a "god", yet what do they mean when they say "god" ? For each person, it is seemingly unique to them, and presumes a standard and accepted definition of the word "god" which is in no way standard or accepted amongst society.
For example, I have friends who claim to be atheist, yet believe in ghosts that they have seen and experienced. I have had friends in the past who would say those ghosts were "gods". Those same atheist friends will then say that they still don't believe in "gods", even though something they witness and experience and DO believe in, is what someone else will call "gods". Thus showing that they already have a conceived expectation of what a "god" should be, even though they claim to lack belief in such a thing, and refuse to accept that term as an application to something else because of that expectation.
Which brings me to my point and question: Rejecting, defying, and ignoring do sound like activities that involve belief to me as well. Does having expectations of what a "god" should be, and rejecting others definition of "god" when they fail to meet those expectations involve belief as well ? I'll refer to my previous example to better illustrate the question:
John claims to be an atheist. He claims to lack belief in gods. He does however believe in ghosts, because he claims to have seen and experienced them, though he cannot explain what they are, he doesn't claim they are "gods". Luke believes in ghosts as well, but believes they are "gods". John rejects the idea they are gods, even though Luke calls them that. His reasoning is that they do not fit the definition of what he would consider a "god". Does that mean that John actually does believe in "gods" in some fashion, since he already has expectations of what they should be, and rejects others definitions because they fail to meet his expectations ? Because to me that sounds like active disbelief, not a lack of having belief in the first place. And if that's the case, how does one know when an atheist is being intellectually honest and actually lacks belief, verses actively disbelieving, rejecting, ignoring, etc ?