I have. That's why I know that the adjectival "atheist" can't be used as you do: there is no dictionary in the world that defines atheist as some view, belief, perspective, etc., such that one can e.g., be a deist or Christian and be "atheist with respect to" Zeus. That's just your nonsense. But just for you, I looked up the adjectival definition as given be the single most comprehensive dictionary of any language in the world: the OED. Guess what? It's this:Atheism is identified in most dictionaries as a word that can be either a verb or an adjective. Look it up.
"Atheistic, impious."
Also, the great thing about the OED is that it gives examples of every sense of every word (in use or no) in the English language, and here we find that the adjectival use of "atheist" is to be understood by the following examples:
"1667 Milton Paradise Lost vi. 370 The Atheist crew.
1821 J. G. Lockhart Valerius II. xi. 316 Borne from its wounded breast an atheist cry Hath pierced the upper and the nether sky."
But lest I skimp out on you here, I will provide the entire definition as given by the OED and you can explain how it is consistent with yours, or even provide a single source that defines the adjectival "atheists" such that a theist can be an atheist with respect to e.g., Zeus:
"atheist, n. and adj.
Pronunciation:
/ˈeɪθiːɪst/
Forms: Also 15 atheyst, 15–16 athist(e.
Etymology: < French athéiste (16th cent. in Littré), or Italian atheista: see atheism n. and -ist suffix.
A. n.
1. One who denies or disbelieves the existence of a God.
[?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 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.
1699 Ld. Shaftesbury Inq. conc. Virtue i. i. 8 To believe nothing of a designing Principle or Mind, nor any cause or 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.
2. One who practically denies the existence of a God by disregard of moral obligation to Him; a godless man.
1577 M. Hanmer tr. Bp. Eusebius in Aunc. Eccl. Hist. iv. xiii. 63 The opinion which they conceaue of you, to be Atheists, or godlesse men.
1656 T. Stanley Hist. Philos. II. viii. 93 An Atheist is taken two waies, for him who is an Enemy to the Gods, and for him who believeth there are no Gods.
1667 Milton Paradise Lost i. 495 When the Priest Turns Atheist, as did Ely's Sons.
1827 J. C. Hare & A. W. Hare Guesses at Truth I. 65 Practically every man is an Atheist, who lives without God in the world.
B. adj.
Atheistic, impious.
1667 Milton Paradise Lost vi. 370 The Atheist crew.
1821 J. G. Lockhart Valerius II. xi. 316 Borne from its wounded breast an atheist cry Hath pierced the upper and the nether sky."