Green’s Dictionary of Slang

1. a female pickpocket or woman thief.

1909		‘The Lang. of Crooks’ in Wash. Post 20 June 4/1: [paraphrasing J. Sullivan] A gun-moll is a woman thief.
1910		J. Sullivan ‘Criminal Sl.’ in Amer. Law Rev. LII (1918) 890: A woman thief is called a ‘gun-moll’.
1924		G. Henderson Keys to Crookdom 411: Gun moll – woman pickpocket.
1937		(con. 1905–25) E.H. Sutherland Professional Thief (1956) 24: Women [...] are naturally exclusive as gun-molls (female pickpockets).
1949		Monteleone Criminal Sl. (rev. edn).

2. a female, gun-carrying gangster or female accomplice of a gun-man.

1918		‘A-No. 1’ Mother of the Hoboes 44: The Rating Of The Tramps [...] 42 Gun Moll: dangerous woman tramp.
1921		Wash. Herald (DC) 27 Apr. 6/5: The murderer was the brother of a beautiful young girl who was used by the slain man as his ‘gun moll’.
1928		M.C. Sharpe Chicago May (1929) 260: Gun Molls, or Trips—women who steal from men in the street, or carry guns.
1931		(con. 1914) C.W. Willemse Behind The Green Lights 291: We [...] found the Greaser’s gun moll, a mighty good looking kid named Laura.
1947		F. Brown Fabulous Clipjoint (1949) 189: I’ve never yet killed a bank robber with a twelve-ounce poker, nor slept with a gun-moll.
1951		Kerouac On the Road (The Orig. Scroll) (2007) 223: Don’t worry, I’m not a gunmoll [...] If you want to come in and search the car, go right ahead.
1961		R. Gover One Hundred Dollar Misunderstanding 79: She started acting like some gun moll.
1963		L.F. Freed Crime in S. Afr. 106: A ‘gun-moll’ is a criminal’s sweetheart.
1989		N. George ‘Kool Moe Dee & L.L. Cool J’ in Buppies, B-Boys, Baps and Bohos (1994) 88: A sepia gun moll with ‘a D.C. haircut and stewardess legs.’.
1992		P. Earley Hot House 302: ‘[Inmate Post] asked me to bring him a handcuff key,’ she said. ‘I couldn’t believe it. I told him, ‘Look, I’m not a gun moll. [...] I’m no Bonnie and Clyde’.
2000		P. Beatty Tuff 59: The testy young gun molls cinched in closer to their respective men.