Violent whirlpool (9)
I believe the answer is:
maelstrom
'violent whirlpool' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for maelstrom that I've seen before include "Large whirlpool" , "Powerful circular current of water" , "Strong circular current of water" , "violent upheaval" , "danger to shipping" .)