Green’s Dictionary of Slang

sweet adj.2

(W.I.)

1. tipsy, slightly drunk.

[WI]cited in Cassidy & LePage Dict. Jam. Eng. (1980).

2. of a man, fashionably dressed, smart.

[US]Kramer & Karr Teen-Age Gangs 119: His dress was in the ‘sweet’ fashion – dark, well-pressed trousers, white shirt, knit black tie with narrow clasp, blue-black corduroy jacket. Flashy clothes were regarded with contempt.
[US]‘Iceberg Slim’ Airtight Willie and Me 51: He’s sweet and loaded.