1. Of low quality, not good, poor, etc.

2. Also used to mean the opposite of it's original meaning, like bad or shit is commonly used (i.e. Wow man, that's some bad moves ya got.). Upstate New York colloquial
That's new car o' yours is wack, how cool.
by BillG February 15, 2005
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the spot between your back and your crack.
the wack is that hairy spot at the bottom of your back before your crack.
by colorian July 2, 2009
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1.The condition of being out of synchronzation with the rest of the universe.
2. Having a twisted or perverse worldview
That BBking53 is so very wack and so is her friend Vandal.
by L. Nettels December 23, 2003
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tha complete sh*t, a fly lil' momma,..a true rider,...
wacktackuliar, wackalicious, wack-around, wanna-wack?, once u've been wack, u never go back,.....as in,....jackee
by wackwack May 16, 2010
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the act of stroking your genitals to an erection, then in rythmic pattern stroke genitals to orgasm.
by asdf August 9, 2003
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One who is wacked.

Reject via popular (and in some cases unpopular) crowd.
me: "Dude, you know CJ?"
Danny: "Yeah, dude, he's such a wack now, ever since he started playing RuneScape and tried to talk to people about it."
by patrick_is_sexy September 20, 2007
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Example: "(during the ultra-sound of newborn)"

(blind)Mr.Brown: wait ur white!
Ms.Brown: Yes
(blind)Mr.Brown: Shitt! our sons gonna be wack!
by redstar69 July 27, 2007
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