A jackknife is also responsible for causing many highway accidents, because when a truck jackknifes, it takes up all the lanes on the highways, and leaves no mercy for the vehicles in its path! Always speed up if you see a jackknife coming toward you if you cannot rapidly get off the highway.
Oh crap dude, that truck is in the process of a jackknife, that piece of shit volkswagon is in our way, guess the only choice we have is to speed up, step on it.
*person in volkswagon*
*ahhhh this is the life, *fart*, beer and hot sauce...boomheadshot.*
Truck Driver: You're right, I wouldn't want to jack knife and cause a wreck.
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.
"Oh, shit! Did you see that car accident? It looked like that tractor-trailer was totally jackknifed!"