Green’s Dictionary of Slang

frogskin n.1

also frog
[such notes are/were green; Franklyn, Dict. of Rhyming Slang (1961), suggests rhy. sl. frogskin = SE sovereign]

1. (US black/campus/Und., also alligator skin, fish-skin, froggyskin) a banknote, $1 bill.

[US]Ade Girl Proposition 104: Although his Salary didn’t make him round-shouldered taking it Home, he was enabled to soak a couple of Frog Skins each Month.
[US]H. Wiley Wildcat 156: Whang! An’ Ah reads six. Frogskin money you gits a furlough.
[US] (ref. to 1898) N. Kimball Amer. Madam (1981) 282: I took the frogskins and said, ‘That’s on account’.
[UK] (ref. to 1918) L. Duncan Over the Wall 21: I learned quickly that a dollar bill was a fish-skin.
Philadelphia Enquirer (PA) 19 Oct. 102/3: Pay day in camp is ‘Uncle Sam’s party’ when frogskins [...] are paid out.
[US]W. Guthrie Seeds of Man (1995) 320: Fork th’ froggyskin.
[US]‘Hal Ellson’ Duke 68: I pulled the score by myself. I was gone about an hour and when I came back I got fistfuls of alligator skins. I got more money than John D and Henry Ford.
[US]H. Braddy ‘Narcotic Argot Along the Mexican Border’ in AS XXX:2 87: FROGSKINS, n. Paper money.
[UK](con. 1940s) G. Morrill Dark Sea Running 29: One frogskin—let’s have it.
[US]‘Iceberg Slim’ Pimp 65: Some broad is going to lay out five hundred frog skins to get her rocks off.
[US]‘Iceberg Slim’ Airtight Willie and Me 13: We got five hundred frog skins.
[US]J. Stahl I, Fatty 163: She’d probably ask me to slip her 50 frogskins a month. [Ibid.] 165: The publisher owed Pathé 50 fishskins.

2. (US Und.) a counterfeit dollar bill.

[US]Flynn’s 16 Jan. n.p.: I had [...] cached about two hundred grand – toad and frog skins, for I never monkeyed with the iron men [DU].

3. (Aus.) a £1 note.

[Aus]Western Mail (Perth) 17 May 26/2: Frogskin, a slang expression for a pound note.
[Aus]Cairns Post (Qld) 4 Jan. 9/3: the green ‘frogskin’ or one pound note.
[Aus]‘Banjo’ Paterson Shearer’s Colt 15: If that bag full of frogskins [pound notes] was burnt in the fire, they’d be some of the iron frame of the bag left, wouldn’t there?
[Aus]Advocate (Burnie, Tas.) 8 Apr. 8/2: Not more than half a frogskin to call your own.
[Aus]R. Park Poor Man’s Orange 102: ‘How much do they sting yer for it?’ ‘Half a frog.’.
[Aus]N. Pulliam I Travelled a Lonely Land (1957) 231/2: carpet (cracker, frog, frogskin) a one – pound note.