Green’s Dictionary of Slang

1. (US) a hijacker.

1965		C. Himes Cotton Comes to Harlem (1967) 152: You’re certain this bale of cotton was carried by the meat delivery truck used by the jackers.
1995		G.A. Haywood ‘And Pray Nobody Sees You’ in Woods Spooks, Spies and Private Eyes (1996) 184: Man, I wasn’t never a jacker! I never pulled nobody out of a car in my life!
1999		J. Ridley Love Is a Racket 164: I tried to get it in my head I really was a jacker and not just some desperate con with a finger in his pocket.

2. a street robber, a thief.

1993		Ice Cube ‘It Was a Good Day’ 🎵 Had to stop at a red light / Looking in my mirror not a jacker in sight.
2003		Dizzee Rascal in Vice Mag. at Hyperdub.com 🌐 Robbers, jackers [...] people who decide they don’t want to shot, are good at taking things.
2007		UGK ‘Swisha And Dosha’ 🎵 ’Fore I fly high, lookin at them jackers in their eye (eye).