Green’s Dictionary of Slang

1. (US drugs) a heroin addict.

1904		NY Tribune 30 Jan. 1/3: Levine is a member of the ‘ncient Order of Hopheads,’ belonging to the class [...] the ‘Light Artillery or Small Gunners’ which means they inject the ‘dope’ into their system with a hypodermic syringe.
1997		Simon & Burns Corner (1998) 23: Pipers and gunners are ranging ceaselessly through the second-floor apartment.

2. (US Und.) a gunman.

1938		E. Hoffman Price ‘Revolt of the Damned’ in Double-Action Gang June 🌐 Suppose the narcotic squad did slug the pants off Keenan’s wounded gunners?
1970		‘Red’ Rudensky Gonif 108: ‘We took the chances!’ the gunner insisted.
2015		J. Spades ‘Anytime I Want’ 🎵 Got a couple gunners that will hollow man Niggas want my spot, I hope you got a plan.

3. (UK black) a firearm.

2015

J. Spades ‘Anytime I Want’ 🎵 Got a couple gunners that will hollow man / Niggas want my spot, I hope you got a plan.