a man, of usually an older age, who is the man. he does whatever he pleases and doesn't care what anybody else thinks. he has a good sense of humor and can be found often laughing at his own jokes. he likes to tell younger men about his stories from back in the day, and most of the stories are legendary. he is respected by all who walk among him. (JACK must be spelled with all capital letters)

"that man over there is JACK and is always telling me crazy stories about his glory days."

JACK by Michiganfan4 November 18, 2009

jack

Absolutely nothing; a shortened form of jack shit or jack squat and a synonym of diddly.

Your wife: "Hi honey...my, you're home late. What did you do today?"
You: "Jack."
Your wife: "How was your day at work?"
You: "What? Where's my dinner?"

jack by Nick D September 9, 2006