Occurs when one poor soul leaves a Facebook account open on a public computer, or any computer for that matter, and gets statuses, pictures, sexual orientation, friends, groups, videos, applications, and all other aspects fucked completely up.

Generally used to teach valuable lessons about locking your shit up.
*Matt has been Facebook Jacked.

Molly: Matt, how drunk were you last night?
Matt: Not very, why?
Molly: You Facebook status says you "got fucked in the ass super hard without lube and you liked it."
Matt: Damnit! They Facebook Jacked me again!!
Molly: Maybe you should learn to lock your shit up.
by 69isthebestnumber April 14, 2009
Get the Facebook Jack mug.
When someone leaves their Facebook logged in and another person comes along and changes their profile picture to a JackFace from the TV series LOST, leaving them in utter humiliation.
Q- "Dude, why did your profile have that weird picture of Jack Shephard from LOST?"
A- "Oh, someone totally Facebook Jacked me."
by TRIVIAMASTERDAD January 29, 2011
Get the Facebook Jacked mug.