Somebody snapping the rough sea? (7)
I believe the answer is:
breaker
'sea?' is the definition.
(thesaurus)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for breaker that I've seen before include "A large wave, sounds destructive" , "Wave hitting the shore" , "from rider disciplining horse?" , "Someone broadcasting on Citizen's Band radio" , "User of CB radio" .)