Aromatic compound (5)
I believe the answer is:
ester
'aromatic compound' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for ester that I've seen before include "Fat" , "radical" , "Organic chemical compound" , "Compound; trees (anag.)" , "Chemical compound of acid and alcohol, found in trees" .)