Woman fighting retail giant (6)
I believe the answer is:
amazon
I believe this clue is a double definition.
'woman fighting' is the first definition.
(type of mythological warrior woman)
'retail giant' is the second definition.
(online retail company)
(Other definitions for amazon that I've seen before include "Strong woman - large river" , "Warlike female" , "seller on the Internet" , "Flower" , "Strong, well-built woman" .)