Flawed sovereign, awfully sour one (9)
I believe the answer is:
erroneous
'flawed' is the definition.
(thesaurus)
'sovereign awfully sour one' is the wordplay.
'sovereign' becomes 'er' (Abbreviation for Elizabeth Regina).
'awfully' indicates anagramming the letters.
'sour'+'one'='sourone'
'sourone' is an anagram of 'roneous'.
'er'+'roneous'='ERRONEOUS'
(Other definitions for erroneous that I've seen before include "Mistaken, in error" , "with mistakes" , "Mistaken - inaccurate" , "Incorrect, wrong" , "not right" .)