Green’s Dictionary of Slang

an ineffectual person.

1990		London Theatre Record 10 1539: [M]odern dialogue that either deflates the antique dignitaries or echoes the steamy street language of the Virgin Queen. ‘Naff off wank-stain,’ remarks one.
1999		A. O’Hagan Our Fathers 9: You stupid fucking tosser. A good slap you’re needing. Get the fuck out the road. Wankstain.
2006		D. Mitchell Black Swan Green 96: Ross kicked the shit out of that wankstain Burch.
2012		(con. 1980s) I. Welsh Skagboys 258: With [...] his cartoon punk Mohawk, he looks just like that wankstain on the postcards they sell at Piccadilly Circus.
2012		J. Fagan Panopticon (2013) 6: Fuck off, wankstain. Stop looking at me.
2012		R. Milward Kimberly’s Capital Punishment (2023) 400: Serving cocktails [...] for wankstains and nice lasses.
2019		Twitter 29 Jan. 🌐 Stop giving these silly old bastards airtime, you useless, complicit wankstains.