The top decoration for a woman (5)
I believe the answer is:
tiara
'the top decoration' is the definition.
(I've seen this before)
'for a woman' is the wordplay.
'for a' becomes 'ti' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'woman' becomes 'Ara'.
'ti'+'ara'='TIARA'
Can you help me to learn more?
(Other definitions for tiara that I've seen before include "Woman's crescent-shaped ornamental headdress" , "Ornamental head gear" , "Half-crown?" , "Small crown" , "Ornamental headpiece" .)