Brewer's: Half-seas Over
Almost up with one. Now applied to a person almost dead drunk. The phrase seems to be a corruption of the Dutch op-zee zober, “over-sea beer,” a strong, heady beverage introduced into Holland from England (Gifford). “Up-zee Freese” is Friezeland beer. The Dutch, half seeunst's over, more than half-sick. (C. K. Steerman.)
“I am half-seas o'er to death.”
I do not like the dulness of your eye, It hath a heavy cast, `tis upsee Dutch.