The face shows a woman’s age (6)
I believe the answer is:
visage
'the face' is the definition.
(visage is a kind of face)
'a woman's age' is the wordplay.
'a woman's' becomes 'vis' (short for Violet).
'vis'+'age'='VISAGE'
'shows' acts as a link.
(Other definitions for visage that I've seen before include "A person's face, countenance" , "Clock" , "Mug" , "Face, aspect" .)