fan, n.¹ — Green’s Dictionary of Slang

fan n.¹

[? Fancy, the n. (1) who sported such garments, or its fan-like expanse across the frame]

(Aus./UK Und.) a waistcoat.

1839		H. Brandon Dict. of the Flash or Cant Lang. 163/1: Fan – a waistcoat.
1847		G.W.M. Reynolds Mysteries of London III 85/1: A Stranger—looked like a spunk fencer. [...] pair of kicksters, a fan, and a dummie .
1856		Manchester Wkly Times 23 Aug. 11/3: The old bloak was propped (squeezed), and his skin drawn from his fan.
1859		Matsell Vocabulum.
c.1863		gloss. in Occurence Book of York River Lockup in Seal (1999) 37: I pulled down a fan and a roll of snow.
1874		Derbyshire Courier 7 Nov. 8/1: Cant language [...] A waistcoat — fan.
1881		Trumble Sl. Dict. (1890).
1882		Sydney Sl. Dict. (2 edn) 4: Fan - Waistcoat.
1889		Clarkson & Richardson Police! 321: A waistcoat ... A fan.
1895		Crowe Aus. Sl. Dict. [as 1882].