Celebrate tum and pert bust (7)
I believe the answer is:
trumpet
'celebrate' is the definition.
(thesaurus)
'tum and pert bust' is the wordplay.
'and' says to put letters next to each other (I've seen this in other clues).
'bust' is an anagram indicator.
'tum' after 'pert' is 'perttum'.
'perttum' anagrammed gives 'TRUMPET'.
(Other definitions for trumpet that I've seen before include "Head" , "Army instrument for signals" , "Shout!" , "brassy type" , "Horn" .)