Green’s Dictionary of Slang

1. (S.Afr.) a general term of approval, usu. from children or young people.

1970		informant in DSAE (1996).
1987		in Fair Lady 8 July 160: In the field of language, or rather, idiom the gap feels as wide as the Fish River Canyon. ‘Hey, that was a really lank joll’ translates into ‘That was a terrific party’ [DSAE].
1991		informant in DSAE (1996).
2010		IOL News (western Cape) 22 Feb. 🌐 Zef isn’t safe; it isn’t lank tit, either, and neither is it schweet, safe or kief, my broer.

2. a good deal, much.

1970		informant in DSAE (1996).
1985		Vula Oct. 32 n.p.: Traditional songs [...] are sung, strange garb is donned and lank vodka is drunk [DSAE].
1992		in Scope 13 Nov. 46 ‘She took lank time,’ he says ... For five weeks he spent every available moment cutting up hundreds of Scope pin-ups to stick together his unique, all-paper nude [DSAE].
2008		IOL News (Western Cape) 11 Aug. 🌐 If you liked Poena is Koning [...] then you will smaak this one lank.
2011		IOL News (Western Cape) 12 Feb. 🌐 A woman calling from the audience [...] said, ‘Ons wag te lank (We’ve waited too long). Let’s get on with this thing’.

3. very.

1987		informant in DSAE (1996).
1991		Fair Lady 8 May 63: Lank = very, as in ‘lank cool’ [DSAE].