Buccaneers arranged a disturbed stretch of water on return (7)
I believe the answer is:
pirates
'buccaneers' is the definition.
('pirate' can be a synonym of 'buccaneer')
'arranged a disturbed stretch of water on return' is the wordplay.
'arranged' becomes 'set' (similar in meaning).
'disturbed stretch of water' becomes 'rip' (I am not sure about this - if you are sure you should believe this answer much more).
'on return' is a reversal indicator.
'set'+'a'+'rip'='setarip'
'setarip' written backwards gives 'PIRATES'.
Can you help me to learn more?
(Other definitions for pirates that I've seen before include "Plagiarists" , "Copies" , "Sea trip (anag.)" , "Copyright infringers" , "Robbers on the high seas" .)