Back in apartheid-era South Africa and, in camera, probably even today, the word 'kaffir' is used in much the same way 'nigger' is used in the western world, ie. as a racist epithet directed at black people.
Recently I realised that Muslims use the word to indicate non-muslims or non-believers. Is there any connection between these two usages?
It (the pejorative usage from South Africa) comes from the Arabic word, see http://www.etymonline.com/index.php?term=kaffir
In Kipling's story 'A Sahib's War', a Sikh is caught up in the Boer War, and says
Kurban Sahib appointed me to the command (what a command for me!) of certain woolly ones--Hubshis--whose touch and shadow are pollution. They were enormous eaters; sleeping on their bellies; laughing without cause; wholly like animals. Some were called Fingoes, and some, I think, Red Kaffirs, but they were all Kaffirs --filth unspeakable.
(Elsewhere he says "Do not let him herd me with these black Kaffirs"; Hubshis are a tribe of Black Indians, presumably used here where a European would say Black.)
So evidently by the turn of the century Kaffir was used in South Africa as a term for non-believers, as a specific term ('Red Kaffirs') for tribes who were non-Muslim among Muslim neighbours (compare Kafiristan, the only Afghan province which was non-Muslim), and as a term of abuse; the descending slope is obvious.
PS Yes, he is fictional, but I have considerably more faith in Kipling's research into Indian use of language than in most historians'.
The Portuguese explorers or slave traders used the term kaffir to refer to African tribes (the term nigger for 'slave' was also of Portuguese origin); the root word comes from the Arabic for 'non-believer'.
In South Africa, it was only really adopted as a derogatory term by soldiers returning from Egypt after the Second World War had ended. The British had introduced a type of caste system, with the British or English being superior, the Boers providing semi-skilled labour, and the kaffirs or blacks being unskilled and landless cheap labourers. South Africa was a British Union until 1961, by which time most of the legislation depriving black people of the right to own land had already been enacted (Land Acts 1910-1913).
The Boers have been unfairly blamed for creating this term; animosity between the races was fueled during the Boer War (a.k.a. the Anglo-Boer War), where the British military armed black groups to attack Boer farms.
So the answer to your question is quite complex: the word has had many derogatory connotations, and has been used in South Africa for many years. The Bantu Wars, a.k.a. the Kaffir Wars, took the form of a long-running skirmish; often, the Boers would side with one group of Xhosas against another Xhosa chief, so it was not strictly a war between Boers and Xhosas. The British again got involved. They drove the Xhosas from their land and taxed the Boer farmers, which spurred the latter to embark on the Great Trek (Groot Trek).
In 1976, the term kaffir was banned as hurtful speech in South Africa.
The Arabic/Islamic kafir has more pejorative overtones than merely "non-believer". It's not just "someone who doesn't share our religious belief"; at least some of the time it's "someone with a different and inferior racial and cultural background to us".
Hence it's not difficult to imagine how white South Africans might have picked up the word and adopted it for their own purpose.
Note that there has been a sizeable Muslim presence in South Africa for as long as there has been a European presence. People of Indian and Middle Eastern origin were less segregated than blacks in Apartheid-era South Africa. Particularly in Cape Town, whites and Arab Muslims lived side by side.
Arabs and Muslims were active in Africa with their slave trade long before the first Europeans arrived. Many Europeans referred to the indigenous population by many various terms eg. savage. As the Muslims had more experience with these people and their behaviours it's therefore not surprizing that their name for them viz. Kaffir, was borrowed by the Europeans. Note that all non Muslims were cruely treated by Muslims irrespective of race. Therefore it's quite possible that Kaffirs were not so much classed as such purely based on their race, but quite possibly also because of their habits and behaviour.
The answer to your question is quite simple as explained in Uncivilized Races of the World Written by J.G Wood and published in 1872. As you stated, Kaffir is the Muslim term for non-believer and Muslims had given that name to the Native tribes Living between the Drakensberg Mountain range near Lesotho and the coast of South Africa long before Europeans first arrived there. The area is also known a Zululand and chief among the Kaffir tribes were the Zulus . My guess is the term Kaffir became derogatory much later having become a reference to the old savage ways.
Kaffir is an purely arabic word that entered the european languages through the influence of muslims, in particular through the biggest and most continuous slave industry that muslims conducted since the time of the muslim prophet of arabia. Kaffir is used as a derogatory term to describe "the vilest of creatures" on earth, non muslims (those who reject islam).
Islam is an apartheid system since it separates the non muslims from the muslims and today, in muslim circles, blacks are still called abed (slave). Slavery is legal in Islam.
Arabic إِنَّ شَرَّ الدَّوَابِّ عِندَ اللَّهِ الَّذِينَ كَفَرُوا فَهُمْ لَا يُؤْمِنُونَ
Transliteration Inna sharra alddawabbi AAinda Allahi allatheena kafaroo fahum la yu/minoona
Literal (Word by Word)
Indeed, (the) worst (of) the living creatures near Allah (are) those who disbelieve, and they (will) not believe.
http://www.islamawakened.com/quran/8/55/
