Nutty quality refined and introduced to stew (7)
I believe the answer is:
madness
'nutty quality' is the definition.
(nutty can informally mean mad)
'refined and introduced to stew' is the wordplay.
'refined' indicates anagramming the letters.
'introduced to' indicates putting letters inside.
'stew' becomes 'mess' (I've seen this before).
'and' with letters rearranged gives 'adn'.
'adn' placed into 'mess' is 'MADNESS'.
(Other definitions for madness that I've seen before include "Folly" , "Utter foolishness" , "great anger" , "Absurdity" , "Lunacy - ska/pop band" .)