Green’s Dictionary of Slang

1. (orig. US) a derog. term for a black person.

1938		X. Herbert Capricornia (1939) 444: You can’t trust them slant-eyed jiggers.
1978		Maledicta II:1+2 (Summer/Winter) 161: Jigger Any black person in contemporary usage, but properly these mean only rural, Southern blacks.
2000		Ebonics Primer at www.dolemite.com 🌐 jigga Definition: 1 a friend Example: Jigga, you best be steppin’ off my quarters an’ dimes.

2. (UK black) a friend.

2018

Loski ‘Cool Kid’ 🎵 Fuck what my bro done, that’s my jigga.