Green’s Dictionary of Slang

1. tipsy.

1985

O. Hawkins Chili 25: A number of people already buzzed out from sips of whatever.

2. (US drugs) asleep or in a stupor from taking so many drugs, or so much of one drug.

1998

L. Stringer Grand Central Winter (1999) 240: Convinced, in my buzzed-out brain, that all the people I passed on the street were clucking their tongues at me.

3. see buzzed adj. (2)