Hero finds oil occasionally (4)
I believe the answer is:
idol
'hero' is the definition.
(I've seen this before)
'finds oil occasionally' is the wordplay.
'occasionally' indicates alternate letters.
'finds'+'oil'='findsoil'
The alternate letters of 'findsoil' are 'IDOL'.
(Other definitions for idol that I've seen before include "Person who is the object of intense admiration as by fan club" , "Much-loved actor" , "Object of false worship" , "Blue-eyed boy" , "loved one" .)