Green’s Dictionary of Slang

toss n.1

[toss (off) v.]

1. in fig. use, something of infinitesimal or zero importance; usu. in phr. not give a toss.

[UK]‘George Eliot’ Daniel Deronda (1967) 363: I don’t care a toss where you are.
[UK] ‘’Arry on ’Igh Life’ in Punch 20 July 24: [He] holds it don’t matter a toss if you finds it swell-togged at a Club.
[UK]G.F. Newman Villain’s Tale 74: ‘Getting a living, Micky, are you?’ the man asked [...] ‘Nothing worth a toss,’ Fielder bemoaned.

2. nonsense.

[UK]K. Amis letter 24 Oct. in Leader (2000) 99: They charge a shilling for that toss.
[UK]N. Griffiths Grits 375: Ploo sah shange or whatever-a fuck it is, tha French toss.

3. see toss-off n.

In phrases

give a toss (v.) (also care a toss)

to care; usu. in negative use, e.g. who gives a toss.

[UK]C. Lee diary 16 Sept. in Eight Bells & Top Masts (2001) 158: Ainslie said i was a mouthy little sod and no one cared a toss what I thought.
[UK]I. Welsh Filth 75: Who gives a toss? The answer is me.
[Aus]R.G. Barrett Mystery Bay Blues 176: Les couldn’t really have given a toss.
[UK]G. Malkani Londonstani (2007) 30: Only the librarian used to give two tosses bout the books an the noise.
[US]C. Black ‘Topless Vampire Bitches’ in C. Rhatigan and N. Bird (eds) Pulp Ink 2 [ebook] A real horro nerd, Jimmy [...] A shame that no one else gave a toss.