its a "l337 sp34k" way of saying "you"

it can also be used as a greeting online instead of saying
yo
w00t!!.OMFG i PWNED j00

"j00 wuz up"

DUDE1:Hey man..
DUDE2:j00..

or

DUDE1:j00..
DUDE2:j00..h0wz it Fr4ggin.
by Agrocybe March 1, 2006
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leet speak (1337) for 'you'

probably comes from the pittsburgh way of saying 'jeet jet'
100|< @ j00!!!!!!!!!11111111111111

gawd i hate leet
by T. Lex June 1, 2005
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j00 phail as in you fail
OMFG you noob j00 phail at everything.
by j.manzano August 8, 2007
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1. when a player in CounterStrike is killed by the suckiest submachinegun, his killer says: UMP j00!
2. At the start of a game of CS a player who buys the UMP submachinegun calls out: UMP J00! to put fear in the hearts of his opponents!
Me: UMP j00 N00BS!
N00b1: OMG I R UMPED!
N00b2: OMG ME TO
by Anonymous September 1, 2003
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1337(leet) for 'fuck you'.
person1:"i iz t3h l337!!!!!!!11"

person2:"fux j00."
by Toxic Tears July 7, 2005
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l337 way of saying "Fuck you"
much more direct and to the point.
timmy :"Man i owned j00 on de_dust yesterday"

eddy :" FucK j00!!!!"
by ant_the_vec October 4, 2003
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