Green’s Dictionary of Slang

a gullible person, one who will ‘swallow’ anything, thus gudgeon-fishing, the ensaring of suckers.

1596		Shakespeare Merchant of Venice I i: Fish not [...] For this fool-gudgeon, this opinion.
1600		Weakest goeth to the Wall line 1155: Now mine Hoste rob pot, emptie kan, Beere sucker, Gudgen, Smelt I should say, haue the women paid thee?
1607		Dekker & Webster Northward Hoe I i: I knowe we shall haue Gudgions bite presently [...] you shall liue like Knights fellowes.
1617		T. Campion poem in Wardroper (1969) 100: With crooked hooks fish thou, as babes do that want reason. / Gudgeons only can be caught with such poor tricks of treason.
1627		J. Taylor ‘An Armado’ in Works (1869) I 91: Traps for vermin, Grinnes for wild Guls, Baytes for tame Fooles, Sprindges for Woodcockes, Pursenets for Connies, Toyles for mad Buckes, Pennes for Geese, Hookes for Gudgeons, Snares for Buzzards, Bridles for old Iades, Curbes for Colts, Pitfals for Bulfinches and Hempen-slips for Asses.
1651		J. Taylor Nonsence upon sence 11: The Gudgeon catcher there, o’er top’d the Nobles.
1664		C. Cotton Virgil Travestie (1765) Bk I 45: And if he be not turn’d t’ a Gudgeon, / We towards Italy will trudge on.
1674		Jackson’s Recantation in C. Hindley Old Bk Collector’s Misc. 15: After I struck a gudgeon, I was sure to hold him, though i suffered him to play a little in the stream.
1683		Whores Rhetorick 205: Men cheat those of another rank, and how they again in a different manner, slur on those same persons, that first made them swallow the Gudgeon.
1699		N. Ward London Spy XIV 337: From thence we Rambled on, like a couple of Sweetners in search of a Country Gudgeon.
c.1700		London-Bawd (1705) 3: Of a Country-Gentleman she makes a Cods-head; and of a rich Citizens Son a Gudgeon.
1714		T. Lucas Lives of the Gamesters (1930) 225: Thus would he catch several gudgeons for his brethren in iniquity.
1722		S. Centlivre Artifice Act II: Do you think to make a Gudgeon out of me?
1734		C. Johnson Hist. of Highwaymen &c. 338: He had sent for some of his Cronies, who paid down Eighty Guineas to get the Gudgeon out of this dry Pond.
1756		Memoirs of an Oxford Scholar 24: They are the Gudgeons the Women of Pleasure angle for.
1772		G. Stevens ‘The Dream’ in Songs Comic and Satyrical 13: So Jack Puddings joke, with distorted grimace, / Benetting their Gudgeons, – the Croud.
1781		G. Parker View of Society II 166: As soon as he has got some gudgeon to bite at his hook and to pick up his pocket, he claims half for being present.
1797		Sporting Mag. May X 114/2: Behold her, how, an ogling, vain Coquette, / Catching male gudgeons in her silver’d net!
1800		Sporting Mag. June XVI 127/2: General Tarleton, as a Fisherman, angled for the Gudgeons most patiently, and met with a bite several times.
1815		‘Betty Brill’ in Vocal Mag. 1 Apr. 118: Pike off, says she, / You dont’ catch me, / For Joey, I’m no gudgeon.
1821		W. Combe Doctor Syntax, Wife (1868) 278/2: The Doctor follow’d in high dudgeon, / At having been so tame a gudgeon.
1834		Satirist (London) 5 Jan. 7/1: The [gambling] dens are now in active, training - for what is expected to turn out ‘a good season’—that is, an abundant harvest for gudgeon-fishing — for catching flats and fools.
1837		Marryat Snarleyyow II 228: He’s charmed, or I am a gudgeon.
1844		New Sprees of London 34: [C]huckling to think that his gudgeon was so easily caught, Bob readily agreed to pay.
1844		J.C. Neal Peter Ploddy and Other Oddities 149: Yes, that’s it – I am – I am a gudgeon!
1850		E.V. Kenealy Goethe: a New Pantomime in Poetical Works 2 (1878) 337: Codger, Spooney, Fogie, Ass, / Vile Mohock, Screw, Gaby, Gudgeon.
1863		Appleton (WI) Motor 5 Mar. 2/4: The horrible rumor of a dreadful fight at Vicksburg is a Copperhead Gold-Panic falsehood, to catch gudgeons.
1873		J.H. Beadle Undeveloped West 93: The horny-handed miner, and the dapper, conservative looking gentleman, are ‘cappers;’ they have borne their part in the game, and ‘hooked a gudgeon.’.
1891		J. Bent Criminal Life 17: Out of many [...] I may mention the following, often used by gamblers for catching the ‘gudgeons’.
1901		W.A. Sun. Times (Perth) 12 May 1/1: A gilt-edged mug was recently driven by ‘Sport’ to more joy than he anticipated [...] the gudgeon, after being drugged and scaled for £25, was deposited in the waiting cab.
1906		E. Hubbard Love, Life and Work 🌐 So the beautiful life they talk of is the bait that covers the hook for gudgeons. You have to accept the superstition.
1922		Broadway Brevities Aug. 35/1: They do say that a certain American millionaire is keeping Flo's trail hot, but that he is far from being the only gudgeon in the lake, as Flo is said to be cutting a swathe across town that makes even the veteran Parisians gasp.
1928		M.C. Sharpe Chicago May (1929) 89: Of course, we had been under heavy expense landing the gudgeon.