Shell supports her in painting atrophied bananas (9)
I believe the answer is:
aphrodite
'shell supports her in painting' is the definition.
(reference to Botticelli's The Birth of Venus)
'atrophied bananas' is the wordplay.
'bananas' is an anagram indicator (informal term for mad).
'atrophied' with letters rearranged gives 'APHRODITE'.
(Other definitions for aphrodite that I've seen before include "Sex goddess" , "Paris gave her an apple" , "got Paris's approval" , "Atrophied like Greek goddess of love" , "Paris prizewinner" .)