Playful river animal (5)
I believe the answer is:
otter
'playful river 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 "Web-footed mammal" , "furry creature" , "fish-eater displayed" , "Aquatic river mammal" , "Carnivorous aquatic mammal" .)