After a month, border commotion (6)
I believe the answer is:
mayhem
'commotion' is the definition.
(thesaurus)
'after a month border' is the wordplay.
'after' means one lot of letters go next to another.
'a month' becomes 'may' (May is an example).
'border' becomes 'hem' (I've seen this before).
'may' next to 'hem' is 'MAYHEM'.
(Other definitions for mayhem that I've seen before include "Carnage" , "Havoc, violent disturbance" , "wild state" , "wilful infliction of injury" , "Havoc - chaos" .)