Compound featured in a cowboy movie essentially (5)
I believe the answer is:
ester
'compound' is the definition.
(ester is a kind of compound)
'movie essentially' is the wordplay.
'movie' becomes 'western' (Western is an example).
'essentially' means to look at the middle letters.
The central letters of 'western' are 'ESTER'.
'featured in a cowboy' is the link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for ester that I've seen before include "Compound formed from acid and alcohol" , "Fat" , "radical" , "Chemical compound of acid and alcohol, found in trees" , "Organic compound, rhymes with court joker" .)