Green’s Dictionary of Slang

a Frenchman.

1780		M.P. Andrews Fire and Water! (1790) 31: Ambuscado This is the Marquis de Crapaud. Launch You are welcome, Mr. Marquis de Croppo. [Ibid.] 34: This is French Marquis [...] the Marquis de Croppo.
1803		J. Wetherell Adventures of John Wetherell (1954) 10 Nov. 78: What the devil were you all about to let the damn’d Croppoes give you such an infernal drubbing?
1826		W.N. Glascock Naval Sketchbk I 30: Every man was at his gun in a crack; and never mind, in closing withCrappo if we didn't buy it with his raking broadsides.
1836		‘Devoted to Mirth & Sarcasm’ Splifincator 1:7 27 Aug. 2/1: Johnny Bull has at length obliged his naughty Parliament to reduce the stamp duty on newspapers to one penny, and Johnny Croppo, on the other side of the channel is obliged to allow the ‘citizen king’ a guard of eighty thousand soldiers.
1836		F. Chamier Ben Brace (3 edn) 6: It was sove ki poo, as the Crapauds say.
1841		W.J. Neale Paul Periwinkle 327: Don’t you think we should be the presarvers of the lives of you and your brave Crappos what are drinking their grog below?
1844		Westmorland Gaz. 10 Aug. 4/5: The astounded ‘Croppos’ instantly complied, without even an effort to escape!
1851		Melville Moby Dick (1907) 350: I well know that these Crappoes of Frenchmen are but poor devils in the fishery.
1853		Kendal Mercury 23 July 6/1: From the long councils of Crapeaus and Teagues, From Papacy rampant [...] Libera nos domine!
1864		J.R. Lowell Fireside Travels 8: There too, are John Bull, Jean Crapaud, Hans Sauerkraut, Pat Murphy, and the rest.
1888		Ally Sloper’s Half-Holiday 12 May 146/3: ‘But you vil admit, Monsieur Slopare,’ said Monsieur Crappaud [etc].
1894		Truth (Sydney) 11 Feb. 1/6: The French and British frontier police have been boring holes through each other at Sierra Leone (W.Af.). Of course it’s a fair kill when Crapaud’s bobby drops.
1896		Regiment 11 Apr. 30/1: Many a long yarn has Pierre spun me about the war [...] declaring that he would greatly like to have another slap at the Crapauds before he ‘“turned up his toes’ .
1983		Maledicta VII 22: French and French Canadian immigrants in this country were called crapaud [...] crapaud was often pronounced ‘crappo’ and ‘crow-poo’ to garnish the loathsome frog.