A Norse converted lady (6)
I believe the answer is:
senora
'lady' is the definition.
(I have seen 'Lady of Spain ' mean 'senora' so perhaps 'lady' could also mean 'senora')
'a norse converted' is the wordplay.
'converted' indicates anagramming the letters.
'a'+'norse'='anorse'
'anorse' anagrammed gives 'SENORA'.
(Other definitions for senora that I've seen before include "Reason with Spanish Mrs" , "Lady of Spain" , "woman from Barcelona" , "Foreign lady; reason (anag.)" , "Mrs or madam (Spanish)" .)