Green’s Dictionary of Slang

a rogue; thus on the picaro, looking for easy opportunities for money-making.

c.1617		J. Howell Epistolæ Ho-Elianæ (1907) 18: I could not recover your diamond Hatband, which the Picaroon snatched from you in the Coach, tho’ I used all Means Possible .
c.1626		Dick of Devonshire in Bullen II (1883) I ii: That word [pox] heard By any lowsy Spanish Picardo Were worth our two neckes. Ile not curse my Diegos.
1675		J. Crowne Country Wit III i: These night-corsairs and Algerines call’d the Watch, that picaroon up and down in the streets.
1677		Behn Rover IV ii: Look on that Wreck, a tight Vessel when he set out of Haven, well trim’d and laden, and see how a Female Piccaroon of this Island of Rogues has shatter’d him.
1685		‘Letter from Julian’ in Wilson Court Satires of the Restoration (1976) 144: That unwholesome foggy air / His fine complexion may impair / Unless his favorite picarre / His master to his old course keeps.
1749		Smollett (trans.) Adventures of Gil Blas III 121: Monsieur de Santillane [...] I see you have been a little on the Picaro in your time.
1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue.
1811		Lex. Balatronicum.
1821		W. Scott Kenilworth II 159: Notwithstanding thy boasted honesty, friend [...] I think I see in thy countenance something of the pedlar – something of the picaroon.
1834		A. Pike ‘Mexican Tale’ Prose Sketches 105: What little silver I have [...] is better bestowed in my big chests than in the pockets of that picaro.
1844		G.W. Kendall Narrative of Texan Santa Fe Expedition II 28: Ochoa was frank and [...] expressed the greatest abhorrence of Salezar and his herd of ladrones and picaros* as he called them (*loafers, scoundrels, thieves).
1847		Bell’s Life in Sydney 23 Oct. 2/4: The Bench [...] dismissed the picaroons.
1860		Hotten Dict. of Modern Sl. etc. 193: Out on the pickaroon PICARONE is Spanish for a thief, but this phrase does not necessarily mean anything dishonest, but ready for anything in the way of excitement to turn up; also to be in search of anything profitable.
1873		Sl. Dict.
1935		A.J. Pollock Und. Speaks 87/2: Picaroon, thief who preys on tourists.
1935		S. Walker Mrs Astor’s Horse 53: There once was a tough picaroon in Chicago named Dion O’Bannion. He was a gangster.