Much admired figure in oil production (4)
I believe the answer is:
idol
'much' is the definition.
Although both the answer and definition are singular nouns, I can't see how they can define each other.
'admired figure in oil production' is the wordplay.
'admired figure' becomes 'd' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'in' indicates putting letters inside.
'production' indicates an anagram.
'oil' anagrammed gives 'iol'.
'd' going into 'iol' is 'IDOL'.
Can you help me to learn more?
(Other definitions for idol that I've seen before include "Worshipped figure (not painting); revered person" , "Pin-up" , "Person who is the object of intense admiration as by fan club" , "Image of a god (not icon)" , "Effigy" .)