Man-eating giantess (6)
I believe the answer is:
ogress
'man-eating giantess' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for ogress that I've seen before include "Monstrous female" , "Terrifying woman" , "Harridan" , "Frightful woman" , "Female giant in fairytale" .)