jack-knife

a semitrailer truck accident where the truck portion folds backwards so that it resembles a jack-knife

I realized I had to take a detour when I heard about the delay caused to a jack-knife on the freeway.

by The Return of Light Joker October 31, 2011

jack-knife

Having deposited your turd in the toilet, you look back to discover that its poking out of the water, too long and solid to go round the u-bend.

I had to go and fetch a stick so I could break up the jack-knife and flush the little devil.

by n_m April 1, 2004

jack-knife

another term for a rude person, synonymous with asshole, jerk, dick, bastard

a way to curse without offending your grandparents

1) Dude, look at that jack-knife over there, what a douche!!
2) Quit being a jack-knife!!

by Jigga JMO September 16, 2008

jack knife

When a trailer being hauled loses traction and begins sliding to the side of the vehicle that is hauling the trailer. Similar to a rear wheel drive vehicle fish tailing and losing control.

Passenger: Dude you better slow down on that turn, its pretty icy out there.

Truck Driver: You're right, I wouldn't want to jack knife and cause a wreck.

by afrojim2009 June 16, 2010

Jack knife

farting while holding ones leg creating a very loud fart.

Wow that jack knife was sOoOoOo loud!!1

by Adam D. April 24, 2006

Jack Knife

A dive in which you jump into a pool , fold in your body with your hands & feet close to each other with the finger tips and toes pointing down, then unfolding bringing your feet to the air and keeping your hands where they are.

person 1 on diving board "HEY GUYS! CHECK OUT THIS JACK KNIFE IM GONNA DO IN THIS POOL!!"
person 2 from a far "YEAH DO IT!"

by Banzai Boy November 23, 2018

Missouri Jack Knife

When a person uses their busted teeth to cut someone during oral sex

I was getting head the other day and that bitch gave me a Missouri Jack Knife!

by loafnaround September 2, 2020