Green’s Dictionary of Slang

(S.Afr.) an obstinate person.

1975		J.H. Picard in Eng. Usage in Southern Africa VI:6 37 : The expression hardegat refers to a most stubborn person — this is of recent coinage [DSAE].
1991		A. Van Wyk Birth of New Afrikaner 68 : I was eventually crowned king of the hardegatte (tough cookies) [DSAE].
1995		I. Mahomed Cheaper Than Roses in Perkins (1998) 58: Me I’m a hardegat so I just stand there.