Fierce killer possibly paroled (7)
I believe the answer is:
leopard
'fierce killer' is the definition.
The answer and definition can be both animals as well as being singular nouns.
Perhaps you can see a link between them that I can't see?
'possibly paroled' is the wordplay.
'possibly' indicates an anagram.
'paroled' is an anagram of 'LEOPARD'.
Can you help me to learn more?
(Other definitions for leopard that I've seen before include "Spotted big cat" , "Spotted feline" , "Spotted beast" , "Animal -- per load (anag)" , "Wild cat" .)