Overreactions bothered music school (13)
I believe the answer is:
conservatoire
'music school' is the definition.
(I've seen this before)
'overreactions bothered' is the wordplay.
'bothered' indicates anagramming the letters.
'overreactions' is an anagram of 'CONSERVATOIRE'.
(Other definitions for conservatoire that I've seen before include "College of arts" , "School of music" , "School of note" , "Music college" .)