Always a woman's right (4)
I believe the answer is:
ever
'always' is the definition.
(synonyms)
'a woman's right' is the wordplay.
'a woman' becomes 'eve' (Eve is an example).
'right' becomes 'r' (common abbreviation).
'eve'+'r'='EVER'
(Other definitions for ever that I've seen before include "Continually" , "Always, at any time" , "Perpetually" , "Possibly" , "Veer away endlessly" .)