Green’s Dictionary of Slang

spiff n.

[spiffy adj.; note retail jargon spiff, a percentage allowed to salesmen when they sell off old or unfashionable stock, thus ‘Mr. Spiffs, the linendraper’ in James Greenwood, Dick Temple (1877)]

1. a dandy.

[UK]Sl. Dict. 303: Spiff a well-dressed man, a ‘swell’.
[US]Eve. Star (Wash., DC) 11 Sept. 20/2: A film was showing a spiff with the booze willies.
[US]M. Levin Reporter 339: The reporter expected the peppy young spiff any minute to [...] make a thumb-to-nose salute.
[UK]M. Marples Public School Slang 6: A spiff was a general slang term for a well-dressed man.
[US](con. 1949) J.G. Dunne True Confessions (1979) 323: It’s one o those flowers the spiffs used to wear in their buttonholes.

2. (also spiffer) something first-rate, exciting, stimulating.

[UK] ‘’Arry on ’onesty’ in Punch 31 Jan. 60/1: The ’igh-flying crickits may splutter, the sleek soapboard crawlers may sniff / But gumptioners know that wot pays is the pink and the spicily spiff.
[UK]Carse & Shand [perf. Ernest Shand] ‘Consequences’ 🎵 Tommy thought, ‘By Jove, / This pond's a spiffer’.

3. (Aus.) a small amount of money.

[Aus]Truth (Perth) 1 Oct. 4/7: The ‘finger’ who will get you / ‘On a string’ / Is a ‘josser’ who has likely / ‘Had a fling;’ / His ‘skyrockets’ then are ‘stiff’ / And he hasn’t got a ‘spiff’ / And he wants to ask you if / You can ‘spring.’ .

In compounds