Green’s Dictionary of Slang

(S.Afr. black) a young man about town; the extended oomackazi is used of young married women.

1963

Wilson & Mafeje Langa 23: Town girls like going out with bright boys – the ikhaba. [...] A little older than the ikaba, from about 25 to 35, is the set called ooMac, from the Scottish Mac, which is a popular nickname among young men in town. [Ibid.] 24: Their wives, ooMackazi, being young married women, are expected to settle down as housewives.