Green’s Dictionary of Slang

1. (drugs) to inject narcotics.

1982

cited in Spears Sl. and Jargon of Drugs and Drink (1986).

2. (drugs) to be intoxicated with a drug, usu. heroin, methamphetamine or crack cocaine.

1985		‘Jennifer Blowdryer’ Modern English 81: tweak (v): When everybody is on speed, they ared tweakin’ out on speed.
1989		N.Y. Times 6 Aug. 20/3: Then there are wounds inflicted with knives, baseball bats and other weapons when drug users are ‘tweaking,’ the street jargon for the volatile behavior that accompanies crack.
1995		J. Stahl Permanent Midnight 91: You’re tweaking [...] Smoking too much of that fucking rock.
2001		J. Stahl Plainclothes Naked (2002) 153: ‘You’re just tweaking is all,’ McCardle protested weakly.
2013		F. Bill Donnybrook [ebook] [Y]ammering that he and Beatle had crashed hard after too many days of tweaking.
2014		M. McBride Swollen Red Sun 26: Jerry Dean was quick to anger when he was [...] tweaking.

3. to suffer heroin or crack cocaine withdrawal or psychosis; thus tweaking n. and adj.

2001		ONDCP Street Terms 22: Tweaking — [...] desperately searching for crack.
2005		Microgram Bulletin XXXVIII:2 35: 🌐 The most dangerous stage of the binge cycle is known as tweaking. During the tweaking stage, the tweaker has not slept in days, becomes paranoid, and has an intense craving for more methamphetamine.
2008		R. Price Lush Life 105: He would rather [...] buy crack from a tweeking biker - anything but deal with the parent of a freshly murdered child .
2012		D. O’Donnell Locked Ward (2013) 171: ‘Tweaking’ is the nickname given to repeated, almost unctrollable movements like swaying, rocking [...] that the sufferer of a drug-induced psychosis might find himself afflicted with.

4. to cause someone problems, to challenge.

1994		M. McAlary Good Cop Bad Cop 183: [He] wasn’t shy [...] about stepping on the toes of feet that had backed away from arresting Michael Dowd and Kenny Eurell years ago. Still, he invited IAD into the case. He wasn’t going to tweak them.
2021		T. Swerdlow Straight Dope [ebook] DreamWorks is out in Burbank and getting there always tweaks me because you have to remember whether it’s east or west on the 134.

5. (US black/campus) to act as if one were intoxicated by drugs, to act energetically or strangely.

1995		J. Stahl Permanent Midnight 252: Legions of herky-jerk, piss-legged mental defectives tweaking down the street.
2000		Ebonics Primer at www.dolemite.com 🌐 tweaking Definition: acting crazy as if high or something. Example: Man you need to quit tweaking.

6. to respond excitedly to a stimulus, e.g. sexual.

1999

T. Fontana ‘The Truth and Nothing But...’ Oz ser. 3 ep. 1 [TV script] The facade would crumble, exposing to those around you what really makes you tweak.

7. to be upset.

2004		Simon & Alvarez ‘Homecoming’ Wire ser. 3 ep. 6 [TV script] Relax, man. I already heard [...] I’m not tweakin’ behind this.
2008		Simon & Burns ‘Stay Frosty’ Generation Kill ep. 6 [TV script] ‘What’s with you, dog?’ ‘I’m tweakin’, bro’.