Green’s Dictionary of Slang

1. a drug addict [var. on junkie n.].

1922		E. Murphy Black Candle 311: When the addict or junker has not the money to obtain his supply from a doctor [...] a pedlar will supply him with the cash [...] it being agreed that the addict will divide evenly with the pedlar.
1930		C.R. Shaw Jack-Roller 157: He seemed to delight in razzing the negroes and ‘junkers’ [...] Junkers (dope fiends) are considered a low class by the guards and get treated like niggers.
1937		(con. 1905–25) E.H. Sutherland Professional Thief (1956) 40: Undoubtedly she was a junker (drug addict) and this is what caused her excitable actions.
1949		Monteleone Criminal Sl. (rev. edn).
1959		Murtagh & Harris Who Live In Shadow (1960) 45: Many of them were ‘social junkers.’ They got together on weekends and ‘shot themselves full’ of heroin.
1966		C. Wood Fill the Stage With Happy Hours (1967) Act I: He has spent the night, our little lad, he has been the night with a junker!
1971		E.E. Landy Underground Dict. (1972).
1989		H. Rawson Dict. of Invective (1991) 223: Junk has produced such terms for confirmed users of narcotics as junk freak, junk hog, junker, and junkie.
1995		J. Stahl Permanent Midnight 77: I was [...] a big-time future junker.
2003		P. Bean Crime: Critical Concepts in Sociology 117: It is a contradiction in terms of addict argot, therefore, to speak of ‘a junker who has never been hooked.’.

2. a drug seller.

1929		Hostetter & Beesley It’s a Racket! 230: junker — A peddler of narcotics or drugs.
1959		J.E. Schmidt Narcotics Lingo and Lore.

3. (US, also junkolo trap, junk pile) a near-derelict but just drivable second-hand car, or motor-bike, one step from the junkyard; also attrib. [junk n.¹ (3a)].

1937		T. Thursday ‘License for Theft’ in Ten Detective Aces Sept. 🌐 No one had ever suggested that Stoneparte Service — The Best in Good Used Cars — was a junkolo trap.
1949		N.Y. Times 1 May 62: A ‘crate’ is a ‘junker’ with ‘one surge left’ [W&F].
1959		E. De Roo Go, Man, Go! 115: No, I can’t identify the driver, I told ya he wore — Huh? There was no plates on that junker.
1965		H.S. Thompson letter 9 Aug. in Proud Highway (1997) 536: I might have to buy one – a junker of some kind, but good enough to hold up for a month or so.
1977		W.P. Kinsella Dance Me Outside 49: That’s why we drive the junker.
1978		S. Longstreet Straw Boss (1979) 212: In his Joe College sports cap and white coveralls, driving this fancy junkpile.
1989		C. Hiaasen Skin Tight 285: Maggie thought it looked ridiculous to be riding in a junker like this and talking on a fancy car phone.
1998		D. Hecht Skull Session 227: I see the junker’s been moved from the bottom of the driveway.
2005		J. LiMarzi Fingers Crossed, Legs Uncrossed 29: When I was 12 years old, a boy down the block got his driver’s license and a junker car.
2008		R. Price Lush Life 236: Money in the bank [...] it’s [i.e. a license plate] been switched with some long-gone junker .
2014		E. Hagelstein ‘Our Lady of Mercy’ in ThugLit Mar. [ebook] I lived in a decrepit trailer park at the time, drove a junker of a Korean compact, and survived.
2020		(con. 1991-94) W. Boyle City of Margins 144: ‘It drives beautifully.’ ‘It’s not a junker,’ Donnie says.

4. (US) as sense 3 but in other contexts.

1999		J. Maple Crime Fighter 21: The more we poked at it [i.e. the police department], the wormier it looked. Operationally, she was a junker.
2021		T. Pluck Boy from County Hell 329: The hacks handed out flak jackets. Andre took one and strapped it onto Jay [...] He rapped on the front. ‘The hacks give us their junkers, but they still work’.