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1 definition by Lapa

 
1.
1. n.-a pocket knife

2. n., v.-person or object that is bent unusually at a 90 degree angle resembling the shapre of an open pocket knife, as in the case of a car accident or physical movements used in disciplines such as diving, gymnastics, yoga, wrestling, etc.

"That diver has incredible technique! Note how he jackknifes his body to move into that maneuver in mid-air."

"Oh, shit! Did you see that car accident? It looked like that tractor-trailer was totally jackknifed!"
by Lapa November 29, 2005