Chalky resolved English court case (10)
I believe the answer is:
cretaceous
'chalky' is the definition.
(thesaurus)
'resolved english court case' is the wordplay.
'resolved' is an anagram indicator.
'english' becomes 'e' (abbreviation).
'e'+'court'+'case'='ecourtcase'
'ecourtcase' anagrammed gives 'CRETACEOUS'.
(Other definitions for cretaceous that I've seen before include "of chalk" , "Chalky" .)