A he-man’s girl (5)
I believe the answer is:
helen
'girl' is the definition.
'a he-man's' is the wordplay.
'man' becomes 'len' (I've seen this in other clues**).
'he'+'len'='HELEN'
(Other definitions for helen that I've seen before include "Greek woman famed for beauty" , "Woman abducted to Troy" , "femme fatale" , "Woman taken to Troy by Paris" , "lady" .)