Cave-in when business gutted local church alcove (8)
I believe the answer is:
collapse
'cave-in' is the definition.
(thesaurus)
'business gutted local church alcove' is the wordplay.
'business' becomes 'co' (short for company).
'gutted' says to hollow out the word (remove centre letters) (to gut something is to remove its insides).
'church alcove' becomes 'apse' (I've seen this in another clue).
'local' with its centre taken out is 'll'.
'co'+'ll'+'apse'='COLLAPSE'
'when' acts as a link.
(Other definitions for collapse that I've seen before include "Fall down or lose strength suddenly" , "Fall or disintergrate" , "Give way or cave in" , "downfall" , "Slump" .)