West Indies importing revolutionary fish paste (6)
I believe the answer is:
wasabi
'paste' is the definition.
(I've seen this before)
'west indies importing revolutionary fish' is the wordplay.
'west indies' becomes 'wi'.
'importing' indicates putting letters inside.
'revolutionary' says the letters should be written in reverse (letters revolve around).
'fish' becomes 'basa' (type of fish).
'basa' back-to-front is 'asab'.
'wi' enclosing 'asab' is 'WASABI'.
(Other definitions for wasabi that I've seen before include "Hollyhock" , "condiment? Japanese actually" , "Pungent green root used in Japanese cookery" , "'Japanese plant, often eaten with raw fish (6)'" , "Pungent green root, used in Japanese cooking" .)