Green’s Dictionary of Slang

1. a very thin person.

1848		Paul Pry 11 Dec. n.p.: We advise young W—ll, alias Rasher of Wind, the omnibus boy [...] to discontinue his tricks at the Royal George, as we are convinced Miss Susan gives him no en- couragement.
1866		Wild Boys of London I 24/1: ‘You hit me, that’s all.’ ‘Hit yer. Why yer five farden rasher of bacon, I’d roll you hup.’.
1912		E. Pugh Harry The Cockney 44: I shouldn’t like him to be a lanky [...] One o’ them there rashers o’ wind like Uncle Algernon.
1941		G. Kersh They Die with Their Boots Clean 76: You, you rasher of wind!

2. a weak, spineless person.

1950

C. Harris Three-Ha’Pence to the Angel 33: The old man, proper little rasher of wind ’e is, always does what ’e’s told.

3. anything of little or no account.

1899

Daily Tel. 7 Ap. 8, 2: Lets ’em howl, an’ sweat, an’ die, an’ goes on all the time, as if they was jest rashers o’ wind [F&H].