So theists are atheists, then?
I haven't met a theist yet who hasn't rejected a god.
It didn't say rejected. It said disbelieve or deny. Theists don't disbelieve in the existence of
a god, but they do deny that some gods exist. The "a" part is a more recent addition as for a long time God meant more or less one thing as far as literate English speakers were concerned. Thus to be an atheist was to deny Judeo-Christian god. Which is ironic, given that the Greek word was applied to Christians because they didn't worship the god
s, and that's what atheos meant.
[?1555 Coverdale tr. Hope of Faythful Pref. f. iiiv, Eate we and drink we lustely, tomorow we shal dy. which al ye Epicures protest openly, & the Italian atheoi.]
1571 A. Golding in tr. J. Calvin On Psalmes of Dauid with Comm. Ep. Ded. sig. *.iii, The Atheistes which say..there is no God.
1604 S. Rowlands Looke to It 23 Thou damned Athist..That doest deny his power which did create thee.
1709 Ld. Shaftesbury Characteristicks (1737) II. i. i. §2. 11 To believe nothing of a designing Principle or Mind, nor any Cause, Measure, or Rule of Things, but Chance..is to be a perfect Atheist.
1876 W. E. Gladstone in Contemp. Rev. June 22 By the Atheist I understand the man who not only holds off, like the sceptic, from the affirmative, but who drives himself, or is driven, to the negative assertion in regard to the whole Unseen, or to the existence of God.
I only use dictionaries, in general, if at least one of three criteria are met:
1) It's a technical dictionary designed to define words rather than help someone understand the definition by reflecting common usages
2) Somebody else quotes a version of the Oxford Dictionary (I really am so pathetic that I look up words in the full OED whenever I can to read the etymology, development in usages, quotes of uses going back hundreds of years in many cases, etc.). I find that it's usually a better definition and if nothing else can get away from the idea that dictionaries tell you what a word means.
3) I think that the definitions given can help clarify the discussion when e.g., someone insists a definition is THE definition and it is either only one of many or isn't even listed.
In this case, the important point was more the issue of disbelieving or denying rather than a "lack of belief". The "a" in the definition is because unlike the time of many of the people quoted in the OED's definition as usage examples, today someone who believes in a god doesn't necessarily believe in the God of (primarily) Western culture after the advent of Christianity. Pagans would have been called atheists because they denied the existence of God, but they believe in
a god so they are no longer considered to be so.