"Nautilus" skipper (4)
I believe the answer is:
nemo
'nautilus skipper' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for nemo that I've seen before include "Finding -, animated film" , "Jules Verne's submarine captain" , "Literary captain" , "Captain of the Nautilus" , "Jules Verne captain" .)