Border demonstration (5)
I believe the answer is:
march
I believe this clue is a double definition.
'border' is the first definition.
(thesaurus)
'demonstration' is the second definition.
(thesaurus)
(Other definitions for march that I've seen before include "Moving demonstration" , "Stride; month" , "Month - proceed" , "Journey undertaken by army etc" , "The month for military movement" .)