“Atheist comes from the Greek atheos, which is built from the roots a- (“without”) and theos (“a god”). Atheism is the doctrine or belief that there is no God.”
“An atheist is one who denies the existence of a personal, transcendent creator of the universe, rather than one who simply lives his life without reference to such a being”.
“In philosophy, the atheist is not just someone who doesn’t accept theism, but more strongly someone who opposes it.” In other words, it is “the denial of theism, the claim that there is no God”.
Atheism in not simply the lack of faith in God, is the positive denial of God existence.
https://www.britannica.com/summary/atheism
Belief in God typically falls within the realm of religion and spirituality. Belief in these other entities is generally associated with folklore, mythology, fairy tales. Is not typically connected to religious or spiritual frameworks, but rather seen as part of folklore and imagination, although belief in demons and spirits can also exist in a religious context.
The greatest philosopher of the XX century, Ludwig Wittgenstein , said that the world is the totality of facts and language the totality of propositions (words, signs, sounds) that signify such facts. Thus, language is the logical figuration of the world. A proposition has meaning if it expresses the possibility of a fact. A fact is expressible in language, which makes language valid, that is, endowed with meaning, the language itself, guaranteeing its agreement with the world.
The existence or non-existence of God cannot be definitively established through empirical evidence or logical analysis.
Thus, beliefs about God would be considered matters of faith or personal conviction. The question of God's existence is not a meaningful one that can be settled through empirical evidence or logical analysis.
Metaphysical propositions are nonsensical because they go beyond what can be meaningfully expressed. These propositions are attempts to express the inexpressible and fall outside the realm of meaningful discourse.
Scientific propositions are different, they correspond to a version of reality. And they are genuine because they represent facts about the world. A scientific theory is an instrument that allows a better or worse understanding and manipulation of nature, of reality, of objects, depending on their correspondence with the facts. And they are constantly evolving because our knowledge of the facts is always evolving.