Show cooperation (7)
I believe the answer is:
concert
I believe this clue is a double definition.
'show' is the first definition.
(I know that concert is a type of performance)
'cooperation' is the second definition.
(thesaurus)
(Other definitions for concert that I've seen before include "Some entertainment" , "Public performance of music" , "Joint action" , "Harmony, performance" , "Musical event" .)