Nothing, or something equivalent to nothing. Jack shit has the remarkable property that its absence and presence are identical. Typically used with or without a negative to describe a total lack of knowledge, value, or significance. Its use carries a strong negative connotation which can express frustration, disdain, ignorance, or other negative qualities.
I don't know jack shit about that. / I know jack shit about that.
It's worth jack shit. / It isn't worth jack shit.
I didn't get jack shit. / I got jack shit.
by cazort June 2, 2005
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Jack is the only son of Awe Schitt and O. Schitt. Awe Schitt, the fertilizer magnate, married O. Schitt, the owner of
Knee-deep Schitt, Inc.
Jack Schitt married Noe Schitt and they had 6 children: Holie Schitt, The twins; Deep Schitt and Dip Schitt, Fulla Schitt, Giva Schitt and Bull Schitt.
Jack and Noe divorced. Noe later married Mr. Sherlock and because her kids were living with them, she wanted to keep her previous name. She was known as Noe Schitt-Sherlock.
Dip Schitt married Loda Schitt and they had Chicken Schitt. Fulla Schitt and Giva Schitt married the Happens
brothers in a dual ceremony.
The Schitt-Happens children are Dawg, Byrd and Horse. Bull Schitt left home to tour the world. He recently returned with his new bride, Pisa Schitt.

Now, when someone say's you don't know Jack Schitt, you can correct them.
- U don't know Jack Schitt
- Yes i do, he's Awe and O. Schitt's son
by Primitiva May 3, 2004
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A term used to describe a lack of anything.
I ain't got jack shit to do. You don't have jack shit. I don't owe you jack shit!
by Carter SN October 2, 2005
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An American gentleman, with whom certain people are unfamiliar.
You don't know Jack Shit.

Perhaps not, but I'm actually on rather good terms with his wealthier cousin Theodore.
by Pipe Downn January 21, 2009
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nothing,ziltch,zero,empty,contains absolutely nothing.
Asked if he had won any money on lotto, sam replied,"nah got jack shit" There was jack shit left in the fridge.
by timothy mark kluwen April 16, 2007
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1) A term most commonly used for when people describe that they don't know, or have not done anything.

2) Probably the name of some guy somewhere, who i'd -really- like to meet.
Bob: "Bill, what do you know about egg products?"

Bill: "Heh, Jack shit, Bob."
by Meik April 2, 2003
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