Pungent Japanese root (6)
I believe the answer is:
wasabi
'pungent japanese root' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for wasabi that I've seen before include "Pungent green root used in Japanese cookery" , "Hot Japanese paste" , "Pungent green paste used in Japanese cuisine" , "Japanese horseradish" , "Pungent green root, used in Japanese cooking" .)