Secure a ship for Othello, perhaps (4)
I believe the answer is:
moor
I believe this is a double definition.
'secure a ship' is the first definition.
(I've seen this in another clue)
'for othello perhaps' is the second definition.
(historical group of Muslims)
(Other definitions for moor that I've seen before include "Make a boat secure - wasteland - Mauritanian" , "Land mainly high" , "Heather-covered tract" , "See 5 Down" , "Room for Moroccan Muslim" .)