Syrup base (3)
I believe the answer is:
sap
'syrup base' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for sap that I've seen before include "Juice; energy" , "Vital plant juice" , "Weaken; tree fluid" , "It's plant juice, idiot" , "One is easily fooled" .)