Jump, vault (4)
I believe the answer is:
leap
I believe this clue is a double definition.
'jump' is the first definition.
(I know that jump can be written as leap)
'vault' is the second definition.
(I've seen this before)
(Other definitions for leap that I've seen before include "Jump a long way" , "'Look before you . . . .'" , "Jump across" , "Basket" , "as 1984 was" .)