Sing a rude song on a pirate ship (7)
I believe the answer is:
corsair
'pirate ship' is the definition.
(corsair is a kind of pirate ship)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for corsair that I've seen before include "Pirate (archaic)" , "Pirate from N. Africa" , "Barbary pirate - pirate ship" , "Seafarer" , "Marauder" .)