Bear with me about a bit of language (Swahili) foibles. This explanation was given to me by the first head of the Africa Inland Church
“Zunguka” means to turn around or go/come around. If you turn around too much or fast/quickly, you get “kizunguzungu” = dizzy/dizzy-ness.
The “White” (or European) person is called an “Nzungu”. Does that mean he is a dizzy person? Maybe?!?
In the early days, there were few “white/European” people running around East Africa compared with the African population. One could go for days on end without seeing one. An African, having been visiting in a distant population center, could have seen one (or more) there.
Suddenly, back in his home area, he sees what he thinks was the one of those same ones he saw in town. He is astounded and asks “When did that man ‘kuzuguka’ (alizunguka hapa lini?) to here”? (“When did that man come around to here?”) He was seen when he had been in that other place and now he has shown up here! They became known as the ones who ‘came around’ to a lot of different places. Some say that our name, “Nzungu”, comes from that early language root. We keep suddenly showing up or coming around [to here] everywhere.
I hope it isn’t meant to say instead that they consider we are “dizzy” people!