Widespread disturbing pain vexes (9)
I believe the answer is:
expansive
'widespread' is the definition.
(thesaurus)
'disturbing pain vexes' is the wordplay.
'disturbing' indicates anagramming the letters (I've seen this in other clues).
'pain'+'vexes'='painvexes'
'painvexes' is an anagram of 'EXPANSIVE'.
(Other definitions for expansive that I've seen before include "Covering a wide area" , "Wide-ranging" , "Lavish" , "Genial" , "Talkative" .)