Cad's deceit, terribly dried out (10)
I believe the answer is:
desiccated
'dried out' is the definition.
(I've seen this before)
'cad's deceit terribly' is the wordplay.
'terribly' is an anagram indicator.
'cads'+'deceit'='cadsdeceit'
'cadsdeceit' with letters rearranged gives 'DESICCATED'.
(Other definitions for desiccated that I've seen before include "without passion" , "sterile" , "dry" , "Dried out" .)