Creeper Jack 

When you steal someone's picture (from facebook, blackberry messenger, etc) without them knowing

Person 1: Hey look at this pic of my friend's birthday cake

Person 2: How did you manage to get that picture? You weren't even there...

Person 1: Oh, I soooo creeper jacked it

Creeper Jack by Ackee2 December 5, 2009

swag-jack 

one who jacks someone's swag

Khushbu Brahmbatt is a swag-jack.

swag-jack by Thug Mr. March 3, 2011

Half-jack 

The process of exciting male genitalia until it is partially erect in order to help the refractory period after getting the first "easy" orgasm out of the way.

Joe half-jacked so that later when he has sex with Jennifer Whoreton he would be able to reduce the time between sexual excursions.

Half-jack by LanguidLover July 19, 2011

Jumping Jack Tutorial 

A male psychological mind trick, mostly used by the female species, the trick is commenced by asking for the male to perform the jumping jack tutorial. The male thinks he is doing jumping jacks but all the female sees is fuckin shlong bouncin.

He is soooo dumb I even tricked him with the jumping jack tutorial on FaceTime. Boys will do anything Jesus.

Jumping Jack Tutorial by Spaggionalgree July 4, 2019

Slack-a-lack-jack 

Slack-a-lack-jack

Means, roughly, "Please endeavor to give me the personal space that i desire while i'm buying, selling, distribting, or using crack cocaine." Old Phoenix (AZ) slang.

Be slack-a-lack-jack, ga'my pipe, ga'my crack!

Slack-a-lack-jack by East Bay Vinny November 16, 2004

To meet jack 

To masturbate/jack off

To meet jack Brb I’m gonna go meet jack; dang I really need to meet jack right now I haven’t in hours.

To meet jack by -_- Jonny is coming -_- March 19, 2020

Defi-jack 

The act of someone stealing your definition on urban dictionary. It starts by you making up your own clever word that you think would be perfect for Urban Dictionary only to see that someone already defined it 3-to-5 years earlier. Results of being defijacked include, but are not limited to: complaing about it on Facebook and or Myspace, telling all your friends that the first definitions were actually you, and suicide.

After using the term "CTS"(Chuckle To Self) for about a week, Sam decided to put it on UD. You can imagine his disapointment when he saw that some punk had Defi-jacked it 3-to-5 years before hand. He immediatly started complaing about it on Facebook and he continued his rant until he decided to kill himself.

Defi-jack by sce1301 July 10, 2010