Why enactment includes an animal (5)
I believe the answer is:
hyena
'an animal' is the definition.
(type of animal)
'why enactment includes' is the wordplay.
'includes' says the answer is hidden in the clue.
'HYENA' is hidden within 'why enactment'.
(Other definitions for hyena that I've seen before include "Carnivorous mammal" , "Beast" , "African carrion-feeder" , "Laughing carnivore" , "Dog-like African carnivore" .)