Green’s Dictionary of Slang

(Aus.) insane; thus as n. a stupid person.

[1869		Teleg., St Kilda [...] Guardian (Melbourne) 24 July 7/4: But, an’ you love me, Mr. Editor, don’t tempt me again in a similar manner, or you’ll drive me to Yarra Bend].
[1898		E.E. Morris Austral Eng. 522/2: Yarra-Bend, n. equivalent to the English word bedlam. The first lunatic asylum of the colony of Victoria stood near Melbourne on a bend of the river Yarra].
[1925		Australasian (Melbourne) 17 Oct. 46/3: ...the spirit born / Of shoddy and of ‘hand-me-downs’ / [...] / It lives and thrives in newer lands, / As fine and fresh as paint, / Where men have gone to Yarra Bend / For much the same complaint ].
1943		Baker Popular Dict. Aus. Sl. (2nd edn).
1950		‘No. 35’ Argot in G. Simes DAUS (1993).
1967		‘Whisper All Aussie Dict.’ in Kings Cross Whisper (Sydney) xliii 11/3: yarra: A stupid person.
1968		J. Alard He who Shoots Last 126: Da foist week I wuz here, I cracked it fer a load of da Sandy McNabs; dey nearly drove me yarra.
1971		J. McNeil Chocolate Frog (1973) 50: ‘Ahh, don’t tell me! Aww, Christ, no! ‘What’se matter? You gone yarra, or somethin’?’.
1986		R. Beckett Dinkum Aussie Dict. 43: Real Yarra: Slightly older version of the above phrase [i.e. real drop kick] meaning that the person is boring and muddy or unclear.
1989		R.G. Barratt ‘Wellington’s On the Other Foot’ in What Do You Reckon (1997) [ebook] One [woman] in particular, not a bad sort but completely Yarramugundi, fancied me.
1998		P. Doyle (con. late 1950s) Amaze Your Friends (2019) 91: ‘Max has flipped.’ ‘Always was half yarra, if you ask me’.
2001		(con. 1945–6) P. Doyle Devil’s Jump (2008) 87: In 1942, Sydney had gone yarra over Americans and all things American.