Conflicts in new arsenal (4)
I believe the answer is:
wars
'conflicts' is the definition.
(war is a kind of conflict)
'in new arsenal' is the wordplay.
'in' indicates a hidden word.
'WARS' can be found hidden inside 'new arsenal'.
(Other definitions for wars that I've seen before include "See 8" , "Armed conflicts against enemies" , "Battles" , "- - of the Roses" .)