It is the South African version of the n-word (I think SA racists also use the n-word, but the k-word carries the same weight. It is an Arabic word meaning "infidel", which means "no faith/belief". Islamic traders down the East African coast used it to refer to non-Muslim inhabitants of Africa.

My first time playing World of Warcraft I wanted to make a fire mage. I wanted the name to sound cool and mystic. My younger self went and kept trying various combinations of words that would imply I was a fire mage. Gotta have the word fire in it, right? What other fantasy sounding prefix can I add to it? Kha sounds cool and mage-y.

Khafire. Way too close to that word and I didn't realize it till weeks later.