Whenever one person is using a PC and another shoves or pushes them out of the way in order to take the computer from them.

Usually occurs between jealous siblings fighting over the same computer.
Person A: Man, I love surfing the internet.
Person B: Let me show you something.
*Person B shoves Person A out of chair.
Person A: Hey, quit keyjacking!
by Casey Sullivan June 27, 2007
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