Atheism is not and has never been unbelief in God, etymologically.

Atheism is formed from the Greek language: a = without, theos=god.
Atheism=without god, Atheist=someone who is without god. Ephesians 2:12
Theism or theist is someone who prostrates and prays to statues and to the elements of the universe or to men. Exodus 20:1-6, Deuteronomy 4, Revelation 14:6-12


Exodus 20:1-6 ASV
(1)  And God spake all these words, saying,
(2)  I am Jehovah thy God, who brought thee out of the land of Egypt, out of the house of bondage.
(3)  Thou shalt have no other gods before me.
(4)  Thou shalt not make unto thee a graven image, nor any likeness of any thing that is in heaven above, or that is in the earth beneath, or that is in the water under the earth:
(5)  thou shalt not bow down thyself unto them, nor serve them; for I Jehovah thy God am a jealous God, visiting the iniquity of the fathers upon the children, upon the third and upon the fourth generation of them that hate me,
(6)  and showing lovingkindness unto thousands of them that love me and keep my commandments.

Deuteronomy 4:15-20 ASV
(15)  Take ye therefore good heed unto yourselves; for ye saw no manner of form on the day that Jehovah spake unto you in Horeb out of the midst of the fire;
(16)  lest ye corrupt yourselves, and make you a graven image in the form of any figure, the likeness of male or female,
(17)  the likeness of any beast that is on the earth, the likeness of any winged bird that flieth in the heavens,
(18)  the likeness of anything that creepeth on the ground, the likeness of any fish that is in the water under the earth;
(19)  and lest thou lift up thine eyes unto heaven, and when thou seest the sun and the moon and the stars, even all the host of heaven, thou be drawn away and worship them, and serve them, which Jehovah thy God hath allotted unto all the peoples under the whole heaven.
(20)  But Jehovah hath taken you, and brought you forth out of the iron furnace, out of Egypt, to be unto him a people of inheritance, as at this day.

The natural born atheists can deny the existence of God

Psalms 14:1 ASV
(1) The fool hath said in his heart, There is no God. They are corrupt, they have done abominable works; There is none that doeth good.

fire unbelief atheists