Make a fuss about old city animal (8)
I believe the answer is:
creature
'animal' is the definition.
(I know that animal can be written as creature)
'make a fuss about old city' is the wordplay.
'make a fuss' becomes 'create' (create can mean to make a fuss or commotion).
'about' means one lot of letters goes inside another.
'old city' becomes 'ur' (ancient city state).
'create' placed around 'ur' is 'CREATURE'.
(Other definitions for creature that I've seen before include "These comforts make life easy" , "Animal or beast" , "Animal or person" , "Brute" , "Bird, beast or fish" .)