The captain, it seems, is a little jumpy (4)
I believe the answer is:
skip
'the captain' is the definition.
(short for skipper)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for skip that I've seen before include "Move with hops and steps" , "Container used to dump rubbish" , "Dumpster -- bypass" , "Omit - refuse container" , "Gambol" .)