Garments Carthaginian leader introduced to African city (6)
I believe the answer is:
Here is my best explanation:
'garments' is the definition.
(tunic is a kind of garment)
'carthaginian leader introduced to african city' is the subsidiary indication.
'leader' suggests taking the first letters.
'introduced to' means one lot of letters goes inside another.
'african city' becomes 'tunis'.
The first letter of 'carthaginian' is 'c'.
'c' placed into 'tunis' is 'tunics'.
(Other definitions for tunics that I've seen before include "'Belted jackets, parts of uniforms (6)'", "Parts of uniforms of school or military", "Military jackets" and "Uniform jackets".)