Green’s Dictionary of Slang

a mistake, a blunder.

c.1786		Grose Classical Dict. of the Vulgar Tongue ms. additions n.p.: Fox’s Paw Faux pas. He or she made a kind of a Foxes Paw.
1788, 1796		Grose Classical Dict. of the Vulgar Tongue (3rd edn) n.p.: FOX’S PAW. The vulgar pronunciation of the French words faux pas. He made a confounded fox’s paw.
1811		Lex. Balatronicum.
1823		Egan Grose’s Classical Dict. of the Vulgar Tongue.