Frisky swimmer (5)
I believe the answer is:
otter
'frisky swimmer' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for otter that I've seen before include "Torte (anag)" , "Aquatic carnivore" , "Fish-eater of the weasel family" , "Holt dweller" , "Fur possibly" .)