Cat losing seconds repeatedly chasing shy rodent (5)
I believe the answer is:
coypu
'rodent' is the definition.
(I know that coypu is a type of rodent)
'cat losing seconds repeatedly chasing shy' is the wordplay.
I cannot really see how this works, but
'shy' could be 'coy' (coy can mean shy or modest) and 'coy' is found within the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for coypu that I've seen before include "S. American "beaver"" , "aquatic mammal" , "Large semiaquatic rodent" , "Aquatic beaver-like rodent" , "South American rodent bred for its fur, nutria" .)