Political opponent in Byzantium (4)
I believe the answer is:
'political opponent' is the definition.
'anti' can be an answer for 'opponent' (someone opposed to something). I'm unsure of the 'political' bit.
'in byzantium' is the wordplay.
'in' indicates the answer is hidden within the clue.
'ANTI' is hidden within 'byzantium'.
Can you help me to learn more?
(Other definitions for anti that I've seen before include "Adversary" , "Hostile" , "Against, informally" , "One who is against (something)" , "(Person who is) not in favour" .)