A name given to a really dark skined person. The name is a hybrid of ken boon, which is rhyming slang for coon. The word 'Sir' is usually given to someone for outstanding efforts in their chosen field, however this is ironically funny, since a person has little influence over their skin colour. Basically a racist term derived from a group of people aptly named 'The Bang Bros Crew'
'man, u see that guy go past, he was a sir ken!'