Green’s Dictionary of Slang

1. a (large) penis.

1879		‘Sub-Umbra, or Sport among the She-noodles’ in Pearl 2 Aug. 5: By Jove, Frank! what a tosser yours has grown since we used to play in bed together a long time ago. I’ll lock the door, we must compare our parts.
1881		Sins of the Cities of the Plain 13: ‘Did you ever see a finer tosser in your life?’ he replied, opening his trousers and exposing a tremendous prick.

2. (Aus.) an affectionate term of address.

1963–74

B. Humphries Barry McKenzie [comic strip] in Complete Barry McKenzie (1988) 100: Any son of Tosser McKenzie’s a mate of mine.

3. (also toss) a despicable, worthless person [the underlying ref. is to masturbation, but the word is not found as ‘a masturbator’ ].

1977		Zigzag Apr. 40/3: She came on in a big mac and flashed her legs like an old tosser before throwing it off .
1988		R. Doyle Commitments 6: I’m Derek fuckin’ Scully, an’ I’m not a tosser.
1992		I. Rankin Wolfman 50: This Jock, this rough-looking tosser in ill-fitting gear.
1994		I. Welsh ‘A Blockage in the System’ in Acid House 78: It disnae matter a fuck whit some fuckin toss in the Labour Party [...] sais.
2001		I. Welsh Glue 51: Ah’m no gaunny even talk tae a toss like that.
2002		D. Flusfeder Gift 305: Never trust anyone who wears red trousers. They’re a tosser.
2009		P. Temple Truth 276: Check the Spirit of Tasmania crew. They’re tossers.
2011		Guardian 26 Mar. 3/2: He enlists shoppers [...] to wave placards, wear David Cameron and Nick Clegg masks and mouth ‘Tosser!’.
2016		in Guardian 30 June 🌐 Just watched the clip [of Boris Johnson]. What an f'ing tosser.
2017		T. Spicer Good Girl Stripped Bare 57: We [i.e. Queenslanders] think Sydneysiders are tossers. But a lot of us want to be those tossers.
2024		J. Meades Empty Wigs (t/s) 297: Tosser. I ignored his little digs. Turned the other cheek.