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
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
i did 4 geygers and i'm twizzacked
by Jethro May 21, 2003
Yeah she's been doing hella twack lately
by Kat November 3, 2004
The sound a bag of quarters makes when it hits someone upside the head, causing this individual to have a lazy eye.
by Schwank November 4, 2004
twack is another word for wack, lame, sum shit tweakers would do
Alicia: lets go to portland

best friend: thats sum twack ass shit
by Cinderlla89 May 28, 2018
Much like a gooch, only the female version.
Damn! I've got an itch on my twack.
by eak April 5, 2004