Surprise performance (4)
I believe the answer is:
turn
I believe this is a double definition.
'surprise' is the first definition.
(thesaurus)
'performance' is the second definition.
(turn is a kind of performance)
(Other definitions for turn that I've seen before include "revolutionary act" , "change for Autumn" , "Go - short walk" , "Revolve; act" , "Spell" .)