1) Unbelievable; insane.

2) Good, bad, or extremely out of the ordinary.

Note: Both definitions an be used in both positive and pejorative sense.
I did horribly on that test. Question 5 was on crack.

I'm so happy I got promoted. My new salary is on crack.

My cell phone is on crack. I need a new one.
by Matthew Morrison July 20, 2006

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Top Definition
Generally someone whose actions would lead one to believe that the person is using crack cocaine due to the stupidity or messed-up-ness of their actions.
Used to describe something stupid, messed up or to express frustration with something
Man, you on crack! You will never get with that chick.

That biology report is on crack man.

Dude, Ms. Stanton's on crack! She gave me a friggen C+!!!
by TheDuke January 25, 2005

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if something is mad, bad or just plain wrong, it can be described as "on crack", or, for added emphasis, "so on crack".
george bush is so on crack.
by robert June 16, 2003

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Also used to describe a person on serious drugs.

Also used to describe a person using Crack-Cocaine.
Jamal is "on crack", thats why he is in the rehab
by Michael January 18, 2005

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The Urban Dictionary T-Shirt

Soft and offensive. Just like you.

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The Urban Dictionary T-Shirt

Smooth, soft, slim fit American Apparel shirt. Custom printed. 100% fine jersey cotton, except for heather grey (90% cotton).

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