Locate female in days (4)
I believe the answer is:
find
'locate' is the definition.
(I know that locate is a more specific form of the action find)
'female in days' is the wordplay.
'female' becomes 'f' (common abbreviation).
'days' becomes 'd' (abbreviation for days).
'f'+'in'+'d'='FIND'
(Other definitions for find that I've seen before include "Track down" , "Realise" , "Locate or discover" , "Discovery" , "Come across" .)