Mr. Jack 

Slang for a police officer that abuses his power, or any police officer in most cases. Made famous by the System Of A Down song of the same name.

Police officer: GET THE FUCK ON THE GROUND BEFORE I BEAT THE SHIT OUT OF YOU!!!
Man: Okay chill out Mr. Jack

Mr. Jack by ThatGregGuy March 31, 2009

Jack ass 

Kanye West

Only a real Jack ass would interrupt a teenager at an award show and embarrass her like that.

Jack ass by SmileyRay December 26, 2009

New Jack 

Short for the word New Jack Swing, used för the music genre that had its biggest years in the late 80's until the mid 90's. It is a hybrid of R&B and sounds like hip hop with a more "swinging" sound on the beats, with the r&b style of singing.

Teddy Riley is said to be the father of New Jack Swing, also Tony Toni Toné, Johnny Gill, Gerald Levert, Bobby Brown, Blackstreet, New Edition and Guy were big names in the New Jack era.
The movie New Jack City (1991) also contains a lot of New Jack Swing music.

"Don't believe a thing about the New Jack Swing!"
-Teddy Riley

New Jack by Caroline B November 2, 2006

Jack-Mormon 

A person who claims to be a 'member' of the Church of Jesus Christ of Latter-Day Saints, but is mostly inactive. Observes some basic principles of 'mormonism', but generally has torn up the rule book. Usually to be found in Utah, where a high concentration of this sect can be found.

A Jack-Mormon often does not observe their guidance of not consuming alcohol or coffee. Can be found to attend the church for say a wedding or funeral. A Jack-Mormon usually, finds themselves at odds with the church. Often this person has been raised in a mormon family unit but come to the conclusion that it does not suit their beliefs.

From experience in Salt Lake City (HQ of Mormonism), this person(typical Jack-Mormon) cannot wait to escape the confines of Utah over the border to Nevada, often going to the small city of Wendover being the nearest to get to, to partake in prostitution, alcohol and gambling.

Jack-Mormon by tictactaylor February 11, 2010

jack in the kacks 

a person who takes delight in sniggering while masturbating themselves without anyones knowledge and the removal of their trousers

Stevie D enjoys a jack in the kacks during free class in the top study

jack in the kacks by aybsteve May 5, 2005

Jack and Zac 

Infamous mixed drink composed of a Jack Daniels (preferrably black label), and powdered Prozac (Fluoxetine).

After a heavy night of drinking, Tony tried a Jack and Zac, followed shortly by his untimely death.

Jack and Zac by Quinnbo Baggins December 10, 2008

Jackaboon 

One who acts stupid, loves being stupid, but doesn't know that they are stupid. Like mixing a jackass with a baboon.

My nose is bleeding. Then stop picking your nose you Jackaboon.

Jackaboon by Mr. Walker-French Teacher January 23, 2009