Gets closer from one arsenal (5)
I believe the answer is:
nears
'gets closer' is the definition.
(to near is to approach or get closer)
'from one arsenal' is the wordplay.
'from' indicates a hidden word.
'NEARS' is hidden within 'one arsenal'.
(Other definitions for nears that I've seen before include "Uses snare to get closer" , "advances" , "Moves closer to" , "Comes closer" , "Draws closer to" .)