Female in fix over first of losses (4)
I believe the answer is:
girl
'female' is the definition.
(girl is a kind of female)
'fix over first of losses' is the wordplay.
'fix' becomes 'rig' (rig can mean to fix or manipulate).
'over' says the letters should be written backwards.
'first of losses' becomes 'l' (1st letter of 'losses').
'rig' written backwards gives 'gir'.
'gir'+'l'='GIRL'
'in' is the link.
(Other definitions for girl that I've seen before include "Maid" , "Lass" , "Young woman" , "See 5" , "A young female" .)