Green’s Dictionary of Slang

(US black) excellent, the very best.

1994		W. Upski Bomb the Suburbs [heading] We Use Words Like Mackadocious.
2002		‘Touré’ Portable Promised Land (ms.) 160: We Words (My Favorite Things) [...] Mackadocious.
2004		C. Downs Secrets and Kisses 51: I did get a short visit from an extra macadocious-lookin’ guy. But the girl he was with was way testy.