Repeat for crashing bore (9)
I believe the answer is:
perforate
'bore' is the definition.
(thesaurus)
'repeat for crashing' is the wordplay.
'crashing' is an anagram indicator.
'repeat'+'for'='repeatfor'
'repeatfor' with letters rearranged gives 'PERFORATE'.
(Other definitions for perforate that I've seen before include "Make hole or holes through" , "punch" , "Puncture" , "pass through hole" , "bore!" .)