Stiff stone having curves (8)
I believe the answer is:
starched
'stiff' is the definition.
(thesaurus)
'stone having curves' is the wordplay.
'stone' becomes 'st'.
'having' is a charade indicator (letters next to each other).
'curves' becomes 'arched' (I can't explain this - if you can you should give a lot more credence to this answer).
'st'+'arched'='STARCHED'
Can you help me to learn more?
(Other definitions for starched that I've seen before include "Stiffened (of shirts)" , "(Of clothes) stiffened" , "(Of fabric) stiffened" , "Made rigid" , "The cards (anag.)" .)