Green’s Dictionary of Slang

a fop or dandy; also as adj.

1675		Head Art of Wheedling 297: That they may not poison their jessimy-Barbers.
1753		Scots Mag. 1 Oct. 18/2: My labour [...] recommended me to the notice of the ladies, and procured me the gentle application of Jessamy.
1753		Adventurer No. 100 n.p.: The scale, however, consists of eight degrees; Greenhorn, Jemmy, Jessamy, Smart, Honest Fellow, Joyous Spirit, Buck, and Blood.
1754		Caledonian Mercury 8 April 1/2: The Sword of State was carried by their Lordships the Earl of Jessamy, and Lord George Fribble.
1772		G. Stevens ‘A Caricature’ in Songs Comic and Satyrical 190: By Terror of Parents, or tempted by Gain, / The Lady resigns to some Jessamy Swain.
c.1786		Grose Classical Dict. of the Vulgar Tongue ms. additions n.p.: Jessamy. A smart jemmy fellow, a fopling.
1788, 1796		Grose Classical Dict. of the Vulgar Tongue (2nd, 3rd edn) .
1811		Lex. Balatronicum [as cit. 1786].
1823		Egan Grose’s Classical Dict. of the Vulgar Tongue [as cit. 1788].
1833		‘Birth of Pollux and Castor’ in Convivialist in Spedding & Watt (eds) Bawdy Songbooks (2011) IV 8: The chap was a stylish young dog, / The most jessamy fellow in life.
1846		Bell’s Life in Sydney 14 Nov. 1/6: ‘The Snobs of England’ [...] There were what used to be called ‘dressy’ Snobs [...] Jessamy, who was conspicuous for his ‘jewellery’, — a young donkey, glittering all over with chains, rings, and shirtstuds.
1853		G.J. Whyte-Melville Digby Grand (1890) 45: Captain Jessamy [...] ‘Lavender Jem,’ as we called him.
1862		Capt. Clutterbuck’s Champagne 263: I can drive straight. Only your jimmy-jessamy conceited muffs that go to smash and endanger ladies’ lives!
1891		in Punch CI:31 Oct. 216: About a month ago I met your friend, ALGERNON JESSAMY. What is there about ALGERNON that inspires such distrust? He is very presentable; some people have gone so far as to call him absolutely good-looking.