Green’s Dictionary of Slang

a drug addict.

[1913		Sat. Eve. Post 15 Feb. in DN IV:ii 127: ‘Coke sniffer,’ explained Tom. ‘They call cocaine crystals snow and a coke user is a sleigh rider.’].
1924		G. Henderson Keys to Crookdom 86: Veteran police officers estimate that two thirds of all the professional robbers are ‘chippy’-users, that is, they ‘play with the white stuff,’ which, in plain English, means that now and then they will ‘shoot’ either cocaine, heroin or morphine.
1937		(con. 1905–25) E.H. Sutherland Professional Thief (1956) 162: Thieves believe that a dope fiend is not as reliable or capable as one who is not a user.
1949		N. Algren Man with the Golden Arm 204: Remember that you’re on the books as a user.
1953		‘William Lee’ Junkie (1966) 57: The owner knew Tony had been a user and had told him to stay off the stuff.
1966		J. Mills Panic in Needle Park (1971) 13: An experienced narcotics cop, or a longtime addict, can with surprising reliability spot a user in a group of twenty people, state with authority what kind of drug he is on, approximately how long it has been since his last fix, and whether or not he is at that moment ‘dirty,’ carrying drugs.
1973		New Yorker 3 July 61: Mostly, the users, even the heroin users, weren’t strung-out hard-core junkies.
1975		D. Goines Inner City Hoodlum 170: Leslie had never thought of Duke as a user.
1986		C. Stroud Close Pursuit (1988) 70: The kid was a user, and I need to know how much of what.
1993		E. Richards Cocaine True 88: The users who huddled there created piles of litter.
2000		P. Temple Dead Point (2008) [ebook] ‘So Robbie went into his garage [...] shot up. that’s it?’ He nodded. ‘The fit’s there?’ A nod. ‘Tracks?’ ‘Yeah. User’.
2001		G. Pelecanos Right As Rain 231: You can bust these kids, see, and you can bust the users, but so what?
2001		D. Looser Boobslang [U. Canterbury D.Phil. thesis] 197/1: user n. a person who uses intravenous drugs.
2010		Codella and Bennett Alphaville (2011) 234: She’s a prostitute and a user with the double dead-dyed gaze of someone who’s surrendered more of themselves than they can ever get back.
2015		G. Disher Heat [ebook] Wyatt thought he’d become skilled at identifying users, but some addicts knew how to hide it.