Beast in duchy enabled to be included (5)
I believe the answer is:
hyena
'beast' is the definition.
(I've seen this before)
'in duchy enabled to be included' is the wordplay.
'to be included' indicates the answer is hidden within the clue (I've seen 'include' mean this).
'HYENA' is hidden in the letters of 'in duchy enabled'.
(Other definitions for hyena that I've seen before include "Wild animal" , "Beast" , "Carrion-eating mammal" , "Laughing carnivore" , "Carnivore with sloping body" .)