coathanger, n. — Green’s Dictionary of Slang

coathanger n.

[the shape]

1. (Aus.) the Sydney Harbour Bridge.

1955		N. Pulliam I Travelled a Lonely Land (1957) 73: Melbourners [...] maliciously refer to it [i.e. Sydney Harbour Bridge] as ‘that old coat hanger.’.
1960		‘Nino Culotta’ Cop This Lot 68: That London Bridge’s not as good as our old Coat Hanger.
1968		S. Gore Holy Smoke 90: Like ’em wantin’ to pull down th’ old Sydney coat-hanger one o’ these days!
1978		T. Davies More Aus. Nicknames 2: Sydney Harbour Bridge has long been known insultingly as The Coathanger.
1986		R. Beckett Dinkum Aussie Dict. 14: Coathanger: The Sydney Harbour Bridge.

2. (Aus.) a Sydneysider.

1996

J. Byrell Lairs, Urgers & Coat-Tuggers 74: The barman [...] looked down at Big Oscar the way Melbourne barmen will do whenever they happen to catch a runaway unwary ‘Coathanger’ (Sydney person) on their turf.

3. (N.Z.) Auckland Harbour Bridge.

2003

McGill Reed Dict. of N.Z. Sl.

In phrases

coathanger whore (n.)

(US) an allegedly promiscuous woman who procures abortions with the aid of an unfurled metal coathanger.

2011

F. Bill ‘Cold, Hard Love’ in Crimes in Southern Indiana [ebook] [of a girl] ‘Carol was a coathanger whore [...] don’t wanna think about how many lives she ended ’fore they even took shape’.