adaggisimo

adaggisimo - noun - An extremely slow tempo marking slower than Largo.

Lumbering and ponderous in slowness. I have played only one piece while I was in high school several years ago that had this marking and it was really difficult to bow (I was playing violin at the time).

oubliette

oubliette – n - A secret dungeon with an opening only in the ceiling, as in certain old castles.