"My Fair Lady” heroine (5)
I believe the answer is:
eliza
'my fair lady heroine' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for eliza that I've seen before include "Miss Doolittle" , "flower-girl in dramatic work" , "- Doolittle (Pygmalion)" , "woman" , "Miss Doolittle/s first name" .)