A portmanteau of "nap" and "accident." When one unintentionally falls asleep, often causing one to miss important engagements.
"I wanted to go to class today, but I had a napcident."
"I napcidentally missed my dentist appointment yesterday."
The opposite of entertaining. Also see: retarded, lame, boring, crap, sucky, etc.
"That movie was so terrible - it was antertaining."