No longer bothered by Verdi works showing greater activity (9)
I believe the answer is:
overdrive
'greater activity' is the definition.
'no longer bothered by verdi works' is the wordplay.
'no longer bothered by' becomes 'over'.
'works' indicates an anagram.
'verdi' with letters rearranged gives 'drive'.
'over'+'drive'='OVERDRIVE'
'showing' is the link.
(Other definitions for overdrive that I've seen before include "gear for cruising" , "Find extra gear" , "Work too hard" , "High gear; excessive activity" , "It gets you going fast" .)