Green’s Dictionary of Slang

neat, undiluted gin.

1627		J. Taylor ‘An Armado’ in Works (1869) I 86: Their fare being [...] oaten-bread, beans, and butter milk, armed upon stark naked.
1789		Both Sides of the Gutter part II 12: Tip him a sup of de naked, to coak de sweat off his eye-brows.
1819		P. Egan Key to the Picture of the Fancy going to a Fight 9: The Link Boy and Mud Larks, in joining their browns together, are for some ‘Stark Naked’.
1820		‘Peter Corcoran’ ‘What is Life?’ in Fancy 105: To take of Deady’s bright stark naked / A glass or so.
1821		Egan Life in London (1869) 265: ‘Come, Covey,’ says I to the landlord [...] ‘let’s have a half a pint of your stark naked.’.
1830		Lytton Paul Clifford I 58: His bingo was unexceptionable; and as for his stark-naked, it was voted the most brilliant thing in nature.
1848		Flash Dict. in Sinks of London Laid Open.
1864, 1867, 1870		Hotten Sl. Dict.
1872		C. Hindley Old Book Collector’s Misc. 37: stark naked — raw spirits.
1882		Sydney Sl. Dict. (2 edn) 8: Stark-naked (orig’n’lly strip-me-naked) - Raw gin.