Atheism
Etymology
From Greek "atheos" (without god), from "a-" (without) and "theos" (god), via French "athéisme." In ancient use "atheos" was often an accusation — the impious, the godless — and the word carried that charge of scandal for most of its history.
noun · /AY-thee-iz-um/
The absence or rejection of belief in the existence of any god.
What it names
A position on one specific question, which is why it is often confused with a whole worldview it does not by itself supply.
Example
His atheism answered only the question of gods; his ethics, he insisted, came from somewhere else entirely.
Related idea
Atheism is a claim about belief in God — there is none; agnosticism is a claim about knowledge — that the answer is unknown or unknowable, so one can be an agnostic atheist without contradiction.