Bony, a maltreated langur (7)
I believe the answer is:
angular
'bony' is the definition.
(thesaurus)
'a maltreated langur' is the wordplay.
'maltreated' is an anagram indicator.
'langur' is an anagram of 'ngular'.
'a'+'ngular'='ANGULAR'
(Other definitions for angular that I've seen before include "With jagged outline" , "stiff" , "Sharp-cornered" , "Skinny" , "Bony, awkward" .)