Woman liable as mistaken (8)
I believe the answer is:
isabella
'woman' is the definition.
'liable as mistaken' is the wordplay.
'mistaken' indicates anagramming the letters.
'liable'+'as'='liableas'
'liableas' with letters rearranged gives 'ISABELLA'.
(Other definitions for isabella that I've seen before include "Spanish queen who was patron of Christopher Columbus" , "Mother of Edward III" , "A queen of Spain" , "Sailable Spanish queen who sponsored Columbus" , "drab colour" .)