Flag leads to violent exchanges at the end of every year (4)
I believe the answer is:
pave
'flag' is the definition.
(thesaurus)
'leads to violent exchanges at the end of every year' is the wordplay.
'leads to' says to take the initial letters.
'at the end of' says to put letters next to each other.
'every year' becomes 'pa' (per annum).
The initial letters of 'violent exchanges' is 've'.
've' after 'pa' is 'PAVE'.
(Other definitions for pave that I've seen before include "Cover with flags" , "Put on a surface of stone slabs" , "Cover with flagstones" , "Dress with stone etc" , "Surface with stone etc." .)