Green’s Dictionary of Slang

gata n.

also gatta
[Sotho sl. legata, a member of the police force, lit. ‘catch a thief’ or gat n.1 , f. their guns; note township sl. amakgathas, arseholes]
(S.Afr.)

1. (also gatte) the police.

[SA]P.C. Venter Soweto 153: Die Gattes – the police.
[SA]A. Brink Dry White Season 87: You think my wife would have opened this time of night? [...] Except for the gattes, of course. The cops.
H. Prendini in Style Oct. 41: Township people try and avoid the ‘gatta’ (police) and the ‘kwela-kwela’ (black maria) by always carrying their ‘stinkers’ (reference books) [DSAE].
[SA]Sophiatown in M. Orkin At the Junction (1995) 204: Watch out! The Gatas are coming!
[SA]A. Lovejoy Acid Alex 101: Ja, the mapuza – Gattas, Boere, Po’lice. [Ibid.] 168 : Ten gattas arrived with pickaxe handles.

2. a prison warder.

[SA]‘Prison Sl.’ in Frontline Oct.–Nov. 15: Gatta – warder.
[SA]A. Lovejoy Acid Alex 212: This gatta is an absolute poes.