Passionate study in oils for example (6)
I believe the answer is:
ardent
'passionate' is the definition.
(similar in meaning)
'study in oils for example' is the wordplay.
'study' becomes 'den' (den can mean an office or study).
'in' is an insertion indicator.
'oils for example' becomes 'art' (I am not sure about this - if you are sure you should believe this answer much more).
'den' inserted into 'art' is 'ARDENT'.
Can you help me to learn more?
(Other definitions for ardent that I've seen before include "passion" , "Fiery and passionate" , "Intensely enthusiastic" , "Loving and fiery" , "Passionate, fervent" .)