Now Arsenal has struggles (4)
I believe the answer is:
wars
'struggles' is the definition.
(I know this)
'now arsenal has' is the wordplay.
'has' says the answer is hidden in the clue.
'WARS' is hidden in the letters of 'now arsenal'.
(Other definitions for wars that I've seen before include "Battles" , "Armed conflicts against enemies" , "- - of the Roses" , "See 8" .)