Fantastic woman is plump for artist (7)
I believe the answer is:
electra
'fantastic woman' is the definition.
(mythical figure)
'plump for artist' is the wordplay.
'plump for' becomes 'elect' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'artist' becomes 'RA' (Royal Academician, member of Royal Academy of Arts).
'elect'+'ra'='ELECTRA'
'is' is the link.
Can you help me to learn more?
(Other definitions for electra that I've seen before include "Mythical woman with a complex?" , "mythological princess" , "Sort of complex" , "King's daughter" , "Greek mythic woman has an odd Celt ear" .)