Really just a sarcastic asshole, can be nice at times but makes you step back and wonder whether or not he's being serious... probably not.
Person: Hey did you hear the joke Jack made the other day?
Person 2: Are you sure he wasn't just being a dick?
Person 2: Are you sure he wasn't just being a dick?
by Henry||| March 20, 2017
Get the Jackmug. 
Jack is a small creature, of Irish origin, known for it's easily disrupted temper and compulsive lying. Jack's love to make threats that they well never deliver, not only this, but they get all up in people's faces when they are challenged, clicking their fingers as they do so, to try and seem larger then they really are. Most Jack's are pessimists, always attention seeking when a problem occurs.
by Mysterious Jack Hunter October 28, 2013
Get the Jackmug. by Theory of Life May 23, 2016
Get the Jack and Tokemug. 
Fat Jack is not your typical jack. Some may call him a simple man, other would define him as a drown to the party. Fat jack doesn't only cock block but also cocks blocks. like I said a simple man.
by Swaggy squirrel November 17, 2020
Get the fat jackmug. Person 1: What’s your name?
Person 2: Jack Mark
Person 1: What’s your favorite color?
Person 2: Jack Mark
Person 2: Jack Mark
Person 1: What’s your favorite color?
Person 2: Jack Mark
by Not_jack_mark November 23, 2021
Get the jack markmug.