It is pretty much short for "Killed it," as in someone messed something up. This slang came about in Redwood City, CA. It is mostly used there.
If someone ruins a joke, you can say "illed it" other phrases can be "Don't ill it" "why you gotta ill it"
by bb_locs(650) April 14, 2009
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Yo Son, you see that ride over there?
Yea boy, that's ill.
by j illa May 28, 2008
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Ill will is the amount of hate you generate from niggas around you
From "The Boondocks":

Riley: "I can't wait for niggas to start hatin', I can't wait."

Huey: "So you judge your success by the amount of ill will you generate from others around you?"

Riely: "Hey, if niggas ain't hatin' on you, you doin' somethin' wrong."
by Boondocks2914 July 22, 2008
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nas's record label named after nas's friend, will, who was killed . also can be used if one of your friends is killed you call them your ill will.
lets go start shit whit em wanna be thugs there.

na nigga they aint no wannabes, nd I dont want you to be my ill will.
by John Calvin Young July 05, 2006
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Verb, Past tense;

an act of deviance usually pertaining to escaping from a situation in which money is required of the escapee.

an act of deception committed towards someone.
"I illed on our tab at the club last night; saved me some $200."

"That bitch was supposed to give me a ride home, but illed on me!"
by XT86 March 27, 2009
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