Hop or leap (4)
I believe the answer is:
jump
I believe this clue is a double definition.
'hop' is the first definition.
(I know that hop is a more specific form of jump)
'leap' is the second definition.
(I know that leap can be written as jump)
(Other definitions for jump that I've seen before include "React with surprise" , "Spring" , "Attack" , "Vault, bound" , "Make abrupt movement - start" .)