Green’s Dictionary of Slang

coguey adj.

also coguy
[Scot. cogue, to drink drams; cogue, a small drinking vessel]

drunk.

[US]B. Franklin ‘Drinkers Dict.’ in Pennsylvania Gazette 6 Jan. in AS XII:2 90: They come to be well understood to signify plainly that A MAN IS DRUNK. [...] Coguy.
[UK]‘Jon Bee’ Dict. of the Turf, the Ring, the Chase, etc.