Green’s Dictionary of Slang

1. (also nierk) to beat up.

1910		East Province Herald 24 May n.p.: They wound up by asserting that they would straightway ‘nierk’ him ... ‘Nierking’ not being a very pleasant proceeding for the ‘nierked,’ Barnard asked ‘What for.’ ‘Never mind! We will nierk you,’ was the only reply [DSAE].
1913		C. Pettman Africanderisms 399: Neuk, [...] This word survives in South Africa with the meaning to hit, strike [...] It is regarded as a coarse word.
1970		informant in DSAE (1996).
1984		Frontline Mar. 18: He and Ou Mike were neuking the souties all over the shop when they stopped the fight to disqualify both sides [DSAE].
1990		P. Cull in Weekend Post 18 Aug. 10: Dr Ferdi Hartzenberg [...] CP ‘will neuk ANC op’ [DSAE].

2. to interfere, to mess with.

1980		Capetonian Aug. 26: Die Merrem, she sez ‘Katie, take die Master’s teef to die dentist in the Main Road’ ... Yerrah, I don’ min tellin’ you, I don’t like to neuk wid teef [DSAE].
1991		informant in DSAE (1996).