Occurring unexpectedly or unintentionally after doing something so stupid, careless or negligent that it should have been obvious that you would run into trouble.
The officer stupidentally shot three other officers while trying to stop a pit bull that was attacking them.
Elliot: No Dr. Murray, I don't want any fries to go with this shake. I don't even know what that means.
Noelle: Excuse me, Dr. Reid
Elliot: What, you want to ask me how many ceiling tiles I've counted this week, or maybe you just want to call me a name like tramp or ho or slesident, which apparently is half slut and half resident