Jump over a cellar (5)
I believe the answer is:
vault
This clue is a double definition.
'jump over' is the first definition.
(to vault is to jump over)
'a cellar' is the second definition.
(I've seen this before)
(Other definitions for vault that I've seen before include "Leap; storage chamber" , "Where bodies may be kept" , "Crypt; leap" , "Secure room -- spring over" , "Strongroom or burial chamber" .)