Green’s Dictionary of Slang

whisker n.1

[SE whisk, to move briskly]

anything excessive, esp. a great lie.

[UK]J. Eachard Hobbs’s State National Letter 35 n.p.: It may be convenient for you to call this [...] a flam, a whisker, a caprice, a piece of fright, malice> calumny and spleen.
[UK]C. Sedley Bellamira I i: These are two Whiskers!
[UK]B.E. Dict. Canting Crew n.p.: Whisker a great Lie.
[UK]New Canting Dict. [as cit. c.1698].
[UK]Bailey Universal Etym. Eng. Dict. [as cit. c.1698].
[UK]B.M. Carew Life and Adventures.
[UK]Grose Classical Dict. of the Vulgar Tongue n.p.: Whisker, a great lye.
[UK]G. Andrewes Dict. Sl. and Cant.
[UK]Lex. Balatronicum [as cit. 1785].
[UK]Egan Grose’s Classical Dict. of the Vulgar Tongue.
[UK]Sussex Advertiser 14 Apr. 4/3: ‘That’s a “whisker”,’ says Phil.
[UK]G. Kent Modern Flash Dict. 35: Whisker – a bouncing lie.
[UK]Flash Dict. in Sinks of London Laid Open [as cit. 1835].
[US]Matsell Vocabulum.
[UK]Hotten Sl. Dict. 269: When an improbable story is told, the remark is, ‘the mother of that was a whisker,’ meaning it is a lie.
[Aus]Crowe Aus. Sl. Dict. 95: Whisker, an enormous lie.