Pop or rap? (4)
I believe the answer is:
bang
I believe this clue is a double definition.
'pop' is the first definition.
(thesaurus)
'rap?' is the second definition.
(thesaurus)
'or' acts as a link.
(Other definitions for bang that I've seen before include "Sudden noise; fringe" , "precisely" , "drug injection" , "Loud noise; fringe" , "Strike violently" .)