Green stone headdress is worn out (5)
I believe the answer is:
jaded
'is worn out' is the definition.
(I've seen this in another clue)
'green stone headdress' is the wordplay.
'green stone' becomes 'jade' (I've seen this before).
'headdress' becomes 'd' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'jade'+'d'='JADED'
Can you help me to learn more?
(Other definitions for jaded that I've seen before include "Worn out or bored" , "No longer freshly keen" , "Very tired or bored stiff" , "Lacking enthusiasm" , "Tired and bored, lacking zest" .)