The condition in which a class or lecture is so undeniably filled with bullshit that one's brain turns off all function. This condition can cause a frustrating and confusing gap in the memory of the affected subject's for the period in which the class or lecture was attended and leaves one stupefied and belligerent.
"Dude, what did I miss in class yesterday?"
"I'm not sure, it was so boring that I had an academic blackout and I can't remember anything"
Someone who routinely goes off-line on Facebook messenger just as you are about to contact them, or if you have even typed in the text box and are about to hit send
John: I tried to message Will the other night, and just as I started typing in "what's up?" he went offline.
Max: Yeah he always gets away at the last second, he's such a Facebook Escapist