Going spare in former empire (7)
I believe the answer is:
persian
'former empire' is the definition.
Although both the answer and definition are singular nouns, I don't see how one could define the other.
'going spare in' is the wordplay.
'spare in' anagrams to 'PERSIAN'.
However, I am not clear how this is indicated.
Can you help me to learn more?
(Other definitions for persian that I've seen before include "Breed of cat" , "From Iran?" , "Type of cat or carpet" , "Long-haired cat" , "Iranian language" .)