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' says the answer is hidden in the clue.
'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" .)