Girl partly Hellenic (5)
I believe the answer is:
ellen
'girl' is the definition.
'partly hellenic' is the wordplay.
'partly' indicates the answer is hidden within the clue (part of the clue is used).
'ELLEN' can be found hidden inside 'hellenic'.
(Other definitions for ellen that I've seen before include "Dame - Terry, English actress" , "Girl" , "Dame - MacArthur, round-the-world sailor" , "the Lady of the Lake" , "It could be Terry" .)