Green’s Dictionary of Slang

1. stupidity, softness; always in have quandongs

2. ext. use of sense 1, personified as a country bumpkin; also as adj.

1914		Bulletin (Sydney) 6 Aug. 32/3: Anyhow, then up comes our quandong friend wot I mentioned before, ole Joe Lovett. W’en we saw ’im we knoo we was all right, ’cos Joe ’adn’t been in for months, an’ was free with his money.
1978		T. Davies More Aus. Nicknames 84: Quandong Was born and bred in the bush.

3. a disreputable figure, living on their wits.

1939		K. Tennant Foveaux 311: In this crowd of low heels, quandongs and ripperty men, she looked at her ease and yet not of them.
1973		F. Huelin ‘Keep Moving’ 178: Quandong, hobo who bludges or imposes on another [AND].
1985		P. Carey Illywhacker 246: ‘What’s an illywhacker?’ [...] ‘A spieler [...] a trickster. A quandong. A ripperty man. A con-man.’.

4. a young woman who accepts any amount of gifts but still refuses to cede her sexual favours.

1967		‘Whisper All Aussie Dict.’ in Kings Cross Whisper (Sydney) xxxviii 10/3: quandong: A girl who makes a practice of remaining virtuous after being wined and dined.
1980		B. Hornadge Aus. Slanguage 197: A woman who refuses to have sex after being wined and dined is called a quandong; the origin of the term is unknown.