Animal, possibly part hen (7)
I believe the answer is:
panther
'animal' is the definition.
(thesaurus)
'possibly part hen' is the wordplay.
'possibly' indicates an anagram.
'part'+'hen'='parthen'
'parthen' anagrammed gives 'PANTHER'.
(Other definitions for panther that I've seen before include "Black leopard" , "kind of feline" , "Big cat" , "Bagheera?" , "animal!" .)