It's a long story, Dave...

It started many centuries ago as "stinking heathen". In time that term became politically incorrect, as it was deemed offensive by a minority of oversensitive types. They put a big guilt trip on everyone else, and people started saying "infidel" instead, for politeness' sake.

A couple centuries later "infidel" also became an impolite term, and was replaced by "Godless Hellhound". You were on safe ground in mixed company as long as you remembered to say "Some of my best friends are Godless Hellhounds, and they're really just like everyone else when you get to know them."

Then a special interest group in Wales declared that "Godless Hellhound" was a term of abuse! Within a decade everyone gave up the term entirely, and you couldn't even speak OF it unless you said "The G.H. phrase...he was using the G.H. phrase!"

This was presently replaced by "non-believer", as it was felt that that was so unexciting that it couldn't possibly offend anyone. But in time it did, probably because it was so unexciting.

"Non-believer" was then replaced by "free thinker", but this implied someone who expects not to pay, so in time "free thinker" also went out of style.

And that was when the modern term "atheist" was adopted. Everyone thought that would be the end of it, but Donuel has advised us otherwise. ;-) The up to date polite term is now "atheian".

Be VERY careful what you call someone who does not believe in God!!!