Green’s Dictionary of Slang

1. (later use US) a drunkard.

1623		Middleton & Rowley Spanish Gypsy I i: It’s as rare to see a Spaniard a drunkard as a German sober [...] I am no borachio.
c.1698		B.E. Dict. Canting Crew n.p.: Boracho, a But, a Drunkard, and a Hogskin.
1700		Congreve Way of the World IV x: How you stink of wine! D’ye think my niece will ever endure such a Borachio!
1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue n.p.: Borachio, a skin for holding wine, commonly a goat’s; also a nick name for a drunkard.
1796		T. Morton Way to Get Married in Inchbold (1808) XXV 81: While you were affluent, the elegant flavour of your Tokay kept down the coarse twang of the borachio in your manners.
1811		Lex. Balatronicum.
1836		C.J. Latrobe Rambler in Mexico 70: When you have said that he was a borrachio you have recorded all the positive evil in his character.

2. a skin for holding wine.

c.1698

see sense 1.