An injury on the shin typically recieved during mountain bike trials. Caused by the pedals ripping flesh from the rider.
Dude! Check out this gnarly kack I got riding yesterday!
by txfreerider January 04, 2007
To bail out or to tell someone that you were going to do something and you don't show.
She said she could do something but the stupid fool kacked-out!
by Corissa August 10, 2004
The strip of skin between the scrotum and anus.
She was rubbing my kack while sucking my cock.
by Dirty Bastard October 25, 2003
it is exactly like the word pack, back and a lot of other words that ryhme with kack but it starts with a k instead of all the other letters
i was writing an essay when i said pack instead of kack
by Poopy Pooperson May 02, 2005