What exactly is an Atheist.

[Caecilian]

The derivation of the word 'atheist' is a seperate issue from that of its meaning. For example, the word 'caterpillar' derives from cater (meaning 'tomcat') and piller (meaning 'despoiler'). And yet caterpillars are not tomcats, and only some of them are despoilers of crops.

For the meaning of a word, look at how it is actually used. In language, 'atheists' are 'people who do not believe in god'. Its very simple, really.

[Thumpalumpacus]

Indeed, it's an effort to define something out of existence.