noun. Sounds kinda mystery-y-ish-y.
Real citation: "is on holiday! Yes!! Now I can have some time to think and let my thoughts run. Lord thank you for your mysterious-osity!"
(June 13, 2009, Twitter, http://twitter.com/IamWeazel/statuses/2152714926)
Made-up citation: "The grandeur of the cosmos is a great and unfathomable mysterious-osity. Also, I think I have a concussion."