Deprimo is a spell which places immense downward pressure upon a target, which may cause the target to fracture.
Hermione Granger used this spell in 1998 to facilitate her, Harry Potter, and Ron Weasley's escape from the Lovegood House. She blasted through a floor so that she, Harry, and Ron fell through, and then Disapparated them in the air.
Etymology
The incantation for this spell is most likely derived from the Latin deprimo, meaning "I press down" or "dig deep"