Green’s Dictionary of Slang

1. left-handed; also as adv.

1886		Sporting Life 7 Apr. 2: Nashville presented her left-handed battery, Earle and Brynan, to offset our ‘lefty’ battery, Krehmyer and O’Leary [OED].
1914		Day Book (Chicago) 3 Apr. 2: Hardly more than boys [...] the youngest, Lefty Louie, but 23.
1939		M. Gross ‘On Broadway’ 6 July [synd. col.] Tad [had] an accident of his right hand which forced him to learn to draw lefty.
1948		(con. 1944) N. Mailer Naked and Dead 465: He remembered the parties that his numbers boss, Left Rizzo, had given.
1952		(con. 1910s) ‘Harry Grey’ Hoods (1953) 7: She means Lefty Louie and Dago Frank.
1960		Mad mag. Sept. 30: That was lefty! Wait’ll you see me throw righty!
1974		(con. late 1940s) E. Thompson Tattoo (1977) 505: He clamped the box between his knees and dipped lefty so he could slip his arm around the back of Sharon’s seat.

2. left-wing, Communistic.

1939		R. Campbell Flowering Rifle 40: As I who’ve lived beneath the two regimes / And have not dreamed the Leftie Teacher’s dreams [OED].
1948		(con. 1944) N. Mailer Naked and Dead 271: That Harvard, goddam lefty outfit.
1977		J. Sayles Union Dues (1978) 75: So it wasn’t some lefty hotshot from Rolling Stone.
1999		Observer Screen 20 June 3: A few trendy leftie comedians too.
2007		M. Rowson Stuff 41: They were clearly some members of a lefty groupuscle.
2020		D. Winslow ‘The Last Ride’ in Broken 323: ‘I ain’t no lefty liberal’.
2021		Betoota-isms 191: Leftie Factory [...] 1. A sandstone university 2. A pretentious tertiary education institution built pre-1900.
2023		R. Sunak q. on Twitter 8 Mar. 🌐 He's [i.e. Keir Starmer] just another lefty lawyer standing in our way.