Arthurian lady (4)
I believe the answer is:
enid
'arthurian lady' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for enid that I've seen before include "Dine with Ms blyton, writer" , "Geraint's wife's" , "'... Blyton, children's author (4)'" , "Geraint's loved one" , "- Blyton, twentith century writer" .)