Green’s Dictionary of Slang

1. (Aus.) a fool [the image of the SE prawn as a ‘humorous’ or ‘stupid’ fish].

1893		D. Healey Cornstalk 50: Well, boys, the ‘Worker’ is a prawn — A fool for all his pains; He has the muscle and the brawn. The ‘Fat Man’ has the brains [AND].
1900		Bulletin (Sydney) 24 Feb. 15/2: Is it a prawn like that could resist the police, yer Warship? Shure if he thried I wouldn’t be conscious av it!
1930		L. Lower Here’s Luck 144: ‘Can’t a man read a paper without you two prawns moaning about it?’ .
1944		L. Glassop We Were the Rats 27: What an odious prawn this Anderson is, I thought.
1951		D. Stivens Jimmy Brockett 263: I nudged Jack and pointed towards the little prawn with my chin. Jack winked back.
1965		W. Dick Bunch of Ratbags 44: The old man became one of the prawns that helped keep those dirty, stinking, rotten, low, mongrel, bastards of leeches that bled the working-man for every penny.
1999		G. Seal Lingo 127: In between [the extremes of insult] lies an enormous and subtly graded range of possibilities that include the following: [...] prawn; prick; right bastard.
2001		N. Barlay Hooky Gear 162: Brawn an brain need raw prawn for dem game. An here I am all use up an raw like a fuckin prawn in a game.
2010		Mail & Guardian (Johannesburg) 14 Jan. 🌐 I referred to the ‘prawns’ hanging around my pavement the other day’.
2010		Mail & Guardian (Johannesburg) 8 Jan. 🌐 I like to use [...] ‘you cheeky fokken prawn!’.

2. (Aus.) a small person [var. on shrimp n. (1a)].

1936

Sun. Mail (Brisbane) 23 Aug. 34/2: There she was, just a little prawn of a woman, standing in the ring, with blonde hair and her arms folded.