Green’s Dictionary of Slang

dud v.2

(Aus. Und.) to misrepresent the origin, quality and value of goods; thus dudding n.

[Aus]J. Alard He who Shoots Last 36: ‘You did go on a dudding trip with Hailstone a few years back?’ [...] ‘That’s correct, we were away selling a bit of dud to tide us over a lean period.’.
[Aus]Bulletin (Sydney) 26 Apr. 44: ‘Anyway how’d you go, Gulcher?’ ‘Went down. Two with a one for duddin’ – unheard of.’ [...] ‘But, Jesus, Gulchy. They give it to you all right, mate. What was you duddin’? The Ampol buildin’ or somethin’?’.
[Aus]R.G. Barrett Real Thing 172: he was also not averse to dudding people with his dope deals should the opportunity ever arise.
[Aus]J. Hibberd Memoirs of an Old Bastard 99: Houn le Pine and his agent [...] would be laughing, as much about the dudding by a country bumpkin of a city slicker as anything else.
[Aus]Smith & Noble Neddy (1998) 247: You know me, Murray, I don’t like fuck-ups. I will not cop anyone trying to dud me by handing me different gear than the sample. [Ibid.] 264: Jones reported back to [the policeman], and they came up with a plan to ensure they didn’t get dudded.
[Aus]Bug (Aus.) 4 Aug. 🌐 So a true league fan is expected to travel all the way to an opposition ground [...] just to see their team dudded by a referee with one ear on the baying home crowd.

In phrases

dud (up) (v.)

(Aus.) to misinform, to cheat, to swindle; thus dudder(-upper) n., one who fraudulently misrepresents the price and/or value of the goods he is selling, e.g. selling dyed aspirins as ‘purple hearts’, or claiming that perfectly legitimately purchased goods are actually ‘off the back of a lorry’ (and thus more glamorous).

[Aus] in K. Tennant Foveaux in DSUE (1984).
[Aus]Baker Drum.
[NZ]G. Newbold Big Huey 248: dud up (v) Fabricate evidence to secure a conviction.
[Aus]J. Byrell (con. 1959) Up the Cross 65: It seems she got dudded by some clown or other.
[Aus]Tupper & Wortley Aus. Prison Sl. Gloss. 🌐 Dud up. To give or sell an article that does not function.
[Aus]R.G. Barratt ‘I Saw That’ in What Do You Reckon (1997) [ebook] Don’t worry about all the poor punters Skase has dudded.
[Aus]P. Temple Broken Shore (2007) [ebook] He as an accountant. Dudded his clients, the pensioners, the little old ladies.
[Aus]C. Hammer Silver [ebook] He ripped of his workers and dudded his creditors.