Additive-free (4)
I believe the answer is:
pure
'additive-free' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for pure that I've seen before include "Free of extraneous elements of any kind" , "Unsoiled" , "Innocent; not mixed" , "Flawless, unsullied" , "Unadulterated" .)