A drunkard. From the Spanish borachoe or borrach'o, a bottle made of pig's skin, with the hair inside, dressed with resin and pitch to keep the wine sweet. (Minsheu.)
“I will, like a true drunkard [borachio ], utter all to thee.” - Act iii. 5.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894