When someone purposefully enters 10 incorrect passwords into your blackberry, causing it to erase all of the information stored on the device.
Tommy: Oh shit! Last night when I was hammered, someone erased everything from my phone!

Franky: Damn man, you got blackjacked!
by TurkishandTommy April 20, 2011
Taking a number 2 and a number 1 at the same time while in the bathroom, thus 21 - the perfect bathroom blackjack.
After 2 hours of being on the road, Lyndon had to take a shit and piss so badly, that he blackjacked as soon as he got in the bathroom.
by Poncho23 November 30, 2015
Masturbating when in a state of black out drunkeness.
I must have been blackjacking last night because i woke up with my dick in my hand.
by Stank Twatwell December 12, 2009
When you skip work to go to the casino and gamble.
Dan couldn't make it to work on Thursday. He had a bad case of blackjackitis.
by Ryguy639 September 7, 2018
a small, light club used for knocking people out
by The Wraith November 6, 2003
A word applied for weed measurements. A blackjack is ¾ oz. (21g).

The word "blackjack" is derived from the popular gambling game, which is often called "21".
- Hey pal, I'd like to buy a blackjack.
- Ight, it'll be 100$.

I smoked that blackjack all by myself!!
by Poulin La-Terreur September 19, 2011
a fan of the k-pop group 2ne1.

in the card game, blackjack equals 21 which not only is pronounced the same as the group's name, but also signifies a win. therefore, the fans are referred to as blackjacks.
person 1: Do you like 2ne1?

person 2: Hell yeah I'm a total BlackJack!
by omgitsshelbyy December 3, 2010