Novel Enid penned about English sovereignty (12)
I believe the answer is:
independence
'sovereignty' is the definition.
(thesaurus)
'novel enid penned about english' is the wordplay.
'novel' indicates anagramming the letters (letters in a new or novel order).
'about' becomes 'c' (abbreviation for 'circa').
'english' becomes 'e' (abbreviation).
'enid'+'penned'='enidpenned'
'enidpenned' is an anagram of 'independen'.
'independen'+'c'+'e'='INDEPENDENCE'
(Other definitions for independence that I've seen before include "Freedom from outside control" , "Self-reliance" , "Freedom from another's authority" , "State of relying only on oneself" , "lack of bias" .)