Definition #1: An action of being completely ignorant when it comes to important stuff such as meals, important phone calls and assignments.
Definition #2: Ignoring the surroundings when it comes to playing online games.
Definition #3: Getting deans list despite no study.
Situation 1
Person 1: Baziq has not been answering my calls for the whole day, I think he is playing LoL.
Person 2: Ah, Baziq has immersed himself in a state of Jet Lee.
Situation 2
Person 69: I got a 4.0 by not studying at all, I have Jet Lee-ed.