Green’s Dictionary of Slang

1. to have sexual intercourse.

1985		B. Simon ‘Outers’ Born in the RSA (1997) 53: Stop your drinking, stop your naaing, stop your rooking.
1990		P.-D. Uys Part Hate Part Love (1994) 40: [They] laughed at his few words of Afrikaans: kak/shit, poep/fart, hol/arse, naai/fuck.
2001		OnLine Dict. of Playground Sl. 🌐 naai v. to perform an act of sexual intercourse with, to fuck. To naai means ‘to fuck’ in a sexual sense.
2005		A. Lovejoy Acid Alex 112: I’m not going to naai you!!

2. thus in fig. use, synon. with fuck about v., fuck with v. etc.

2001

OnLine Dict. of Playground Sl. 🌐 naaied v. being ‘messed around’ For example ‘He naaied her last night’, ‘He got naaied by the headmaster.’ [...] To get naaied means to be ‘fucked around’ in a non sexual sense.