Being from Milan, a revolutionary (6)
I believe the answer is:
animal
'being' is the definition.
(animal is a kind of being)
'milan a revolutionary' is the wordplay.
'revolutionary' is an anagram indicator.
'milan'+'a'='milana'
'milana' is an anagram of 'ANIMAL'.
'from' is the link.
(Other definitions for animal that I've seen before include "It shares the world with vegetable and mineral" , "Animate being" , "Mammal" , "Beastly" , "Organism having life" .)