Quick-witted, casting statue (6)
I believe the answer is:
astute
'quick-witted' is the definition.
(thesaurus)
'casting statue' is the wordplay.
'casting' indicates an anagram.
'statue' with letters rearranged gives 'ASTUTE'.
(Other definitions for astute that I've seen before include "Able to make accurate assessments" , "on the ball" , "Sharp-witted" , "Subtle" , "Wise" .)