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2.
TWACK v. To strike with great force using the back of the middle finger (usually the nail) after coiling it under pressure against the opposing thumb. Accomplished twackers can inflict great welts upon their victim's flesh. (This definition posted by the forerunner was removed from the Urban Dictionary by some evil force... but truth shall prevail!)
That turd cutter pissed me off, so I twacked him right in the munt!
"on the first twack//pope jumped like a macaque//on the second twack//pope was taken aback//on the third twack//lost his marbles the old hack" (A.S. Pushkin)
by Clittary Hilton September 17, 2006
 
1.
TWACK v. To strike with great force using the back of the middle finger (usually the nail) after coiling it under pressure against the opposing thumb. Accomplished twackers can inflict great welts upon their victim's flesh.
That turd cutter pissed me off, so I twacked him right in the munt!

On the first twack
Pope jumped like a macaque;
On the second twack
Pope was taken aback;
On the third twack
Lost his marbles the old hack.
(A. S. Pushkin)
by Clittary Hilton October 31, 2007
 
3.
1. Another word for Crystal Methamphetamine.

2. Common objects associated with crystal methamphetamine. These objects can be signs that junkies are present or were there recently (maybe crashed on the floor/couch). These things include really crappy drawings of graffiti on scrap paper, uncleaned dog poo/drinks/food on the carpet, broken light bulbs/missing light bulbs (can be improvised to smoke meth), crafty arts that require short attention spans (for females), left-over traces of meth on the coffee table, and other various tweaker paraphernalia.
1. Yo man you got some of that twack?(twacktonite)

2. Man i got home last night and my room mate had twack all over the living room!
by Smurf October 04, 2006
 
4.
to be super tweaked
i did 4 geygers and i'm twizzacked
by Jethro May 21, 2003
 
5.
slang for methamphetamine
Yeah she's been doing hella twack lately
by Kat November 03, 2004
 
6.
The sound a bag of quarters makes when it hits someone upside the head, causing this individual to have a lazy eye.
that twack ass bitch can't even see straight
by Schwank November 03, 2004
 
7.
A twitterer who constantly checks his/her twitter account hoping that the celebrity they stalk will respond to something they commented on that particular persons page.
Darryl - "Why do you look so tired?"
Leroy - "I was up all night waiting to see if Jon Stamos said thanks for telling him his ass would make a great helmet."
Darryl - "God your a twack! Well...did he?"
Leroy - "(weeping) no!"

Darryl - ".....Would mine??"
(long, awkward pause)
by Darryl&Leroy May 21, 2009