It could accompany light stew? Sense otherwise (9)
I believe the answer is:
sweetness
'it could accompany light' is the definition.
(as in the phrase 'all light and sweetness')
'stew? sense otherwise' is the wordplay.
'otherwise' indicates anagramming the letters.
'stew'+'sense'='stewsense'
'stewsense' is an anagram of 'SWEETNESS'.
(Other definitions for sweetness that I've seen before include "Amiability" , "Light accompaniment for this" , "Sugary quality" , "appearing reasonable?" , "Fresh quality (of water); one with light" .)