Signs provided by females ousting head (5)
I believe the answer is:
omens
'signs' is the definition.
(I know this)
'provided by females ousting head' is the wordplay.
'provided by females' becomes 'women's' (provided by women).
'ousting head' means to remove the first letter.
'womens' with its initial letter removed is 'OMENS'.
(Other definitions for omens that I've seen before include "Augurs" , "Prophetic signs of good or evil" , "Prognostications" , "Signs of things to come" , "Auguries" .)