Rub ingredient (5)
I believe the answer is:
spice
'rub ingredient' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for spice that I've seen before include "Eg, turmeric" , "Aromatic flavouring" , "Eg, cinnamon" , "Pungent flavouring" , "eg Mace, ginger, Posh" .)