In Swahili (the lingua franca of East Africa): someone who wanders without purpose / someone constantly on the move.
It came to be applied to all white people in East Africa, as most were encountered as traders, visiting colonial officials or tourists.
Today, white tourists are often greeted (especially by children) with the cry: "Bye bye mzungu!"
For some reason, they rarely say "Hello mzungu!" when they see one coming...
Child: "Bye bye mzungu!"
Indignant white person: "Listen, it's 'hello mzungu!' - and anyway, I've lived here for 25 years, you cheeky devil."
Child: (pause) "Bye bye mzungu!"
or
Ugandan Stall-holder: "A bowl of passion fruit? Um... that'll be 3,000 shillings please."
Indignant white person: "Come again? I'm not paying mzungu prices, I've lived here 25 years!" etc. etc.
A medium to large sized house, that is well kept yet vacant - having been bought by banks, house flippers or speculators for the sole sake of investment, like a gold brick, rather than being used to live in. One of the major reasons for the high prices of housing, and also the shortage of 𝘢𝘧𝘧𝘰𝘳𝘥𝘢𝘣𝘭𝘦 housing.
Drove through this nice neighborhood, but noticed a lot of empty homes with no "for sale" signs. But later I found all those houses are half a million each, even though they aren't that big. Seem those empty homes are gold bricked houses.