means Full of juice, or by extension richly interesting, lucrative, or scandalously appealing.

from From 'juice' (Middle English 'jus,' borrowed from Old French and ultimately Latin 'ius,' meaning broth, sauce, or liquid) plus the adjective ending '-y.' The literal sense — dripping with liquid, as in a peach or a roast — came first; the figurative leap to 'juicy gossip' and 'a juicy deal' is a much later flowering, where the idea of something rich and saturated got applied to anything pleasurably full of substance.