Playful aquatic animal (5)
I believe the answer is:
otter
'playful aquatic animal' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for otter that I've seen before include "Aquatic beast" , "Water creature" , "Freshwater carnivorous mammal with webbed and clawed feet" , "fish-eater displayed" , "river in Honiton" .)