Green’s Dictionary of Slang

(S.Afr.) a goatee beard.

1913		C. Pettman Africanderisms 75: Bokbaard, [...] A chin beard like that of a goat.
1978		P. Strauss in Contrast 46 12:2 6: They’re absorbed in the visit Of Mistah Pan the wood-god, Squatting on goat-legs [...] Nodding his bokbaard wise-sheep face, A male without troubles [DSAE].
1982		C. Hope Private Parts 45: A bokbaard tapering to an exquisite point adorned his chin.