Conductor's upset (6)
I believe the answer is:
rattle
I believe this is a double definition.
'conductor's' is the first definition.
(Rattle is an orchestra conductor)
'upset' is the second definition.
(thesaurus)
(Other definitions for rattle that I've seen before include "Let rat make the sound" , "Trivial talk" , "Baby's toy; irritate" , "American snake" , "Baby's toy - conductor" .)