African capital importing 100 garments (6)
I believe the answer is:
tunics
'garments' is the definition.
(tunic is a kind of garment)
'african capital importing 100' is the wordplay.
'african capital' becomes 'tunis' (capital of Tunisia).
'importing' is an insertion indicator.
'100' becomes 'C' (Roman numeral).
'tunis' placed around 'c' is 'TUNICS'.
(Other definitions for tunics that I've seen before include "Uniform jackets" , "Parts of uniforms of school or military" , "'Belted jackets, parts of uniforms (6)'" , "Military jackets" .)