KAFIR

[Maketakunai]

Opinion insertion hurts a lot; it can tear your anus too. So I dislike it and won't do it.

I don't think you should either.  Be awful to get a paper cut in such a tender area.

atheist
/ˈeɪθɪɪst/
noun
noun: atheist; plural noun: atheists
a person who disbelieves or lacks belief in the existence of God or gods.
"he is a committed atheist"
synonyms:
non-believer, non-theist, disbeliever, unbeliever, heretic, sceptic, doubter, doubting Thomas, agnostic, infidel, irreligious person, heathen, pagan, freethinker, libertine, nihilist; More

But nothing there says that atheists 'literally...don't believe in anything', which was your contention.

AKA you're a Kaffir.

You give the impression (and I sincerely hope I'm wrong about this) that you know the current meaning of 'kaffir' but are using the pretense of the historical meaning to give yourself a pass.  This is like people who contend that 'nigger' isn't a vile, hateful word because it once meant 'Negro'.

Boru

I remember the word being used by the South Africans in the movie Die Hard, so I looked it up.

Originally the word kefir referred to just the Xhosa tribe. In the early 1800's the British were trying to keep the peace between South African tribes after 3 or 4 tribal wars that were threatening British rule. The Xhosa tribe decided to take up arms against the British. The word kefir has some significant meaning specific to the tribal costume of the Xhosa tribe. The Brits adopted the word to describe that specific tribe. There was a unit of British soldiers who were assigned the duty of keeping the Xhosa tribe under control and the duty was considered to be so bad that other soldiers referred to the unit as the Kefir police. Over time kefir became kaffir and was used as a reference to all black people. During Apartheid it became a popular derogatory term referring to all black people.  

The two words sound the same, but they have completely different meanings. It only means nigger in SA Afrikaner.