Green’s Dictionary of Slang

(S.Afr.) ‘guts’, both lit. and fig., i.e. courage, bravery, staying power.

1970		informant in DSAE (1996) Derems. Innards [DSAE].
1978		in Darling 30 Aug. 123: I’m sommer building up the suspense, see? [...]. Keep yore readers dangeling [...], then zap them in the derems with yore punch-line [DSAE].
1985		Daily News 29 Jan. 25: I just loved your idea about removing the engine and using the starter motor of the car. It made me wonder what other derms could be removed from my car [DSAE].