Drinking wine, conservative editor is happy (9)
I believe the answer is:
contented
'is happy' is the definition.
(associated in meaning)
'drinking wine conservative editor' is the wordplay.
'drinking' indicates putting letters inside.
'wine' becomes 'tent' (type of Spanish wine).
'conservative editor' becomes 'coned' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'tent' put inside 'coned' is 'CONTENTED'.
Can you help me to learn more?
(Other definitions for contented that I've seen before include "Satisfied with things as they are" , "Not decent (anag) - cheerful" , "Feeling satisfied" , "'Satisfied, relaxed and happy (9)'" .)