Green’s Dictionary of Slang

(US black) admirable, aware, ‘hip’; lit. one who ‘digs’.

1993		Snoop Doggy Dogg ‘Tha Shiznit’ 🎵 But now I make hits, every single day / With that nigga the diggy Dr. Dre.
1999		Dr Dre ‘Bitch Ass Niggaz’ 🎵 You don’t want no trouble with the Aftermath staff, trust me / Doggy Dogg, Diggy Doctor plus me.