Viscous liquid from green or black fruit (5,3)
I believe the answer is:
olive oil
'viscous liquid from green or black fruit' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for olive oil that I've seen before include "Pressed cooking ingredient" , "Substance pressed from fruit" , "Ingredient of vinaigrette" , "Viscous liquid from green or black fruit" , "dressing maybe" .)