New troubles mean arrests (5)
I believe the answer is:
nails
'arrests' is the definition.
('nail' can be a synonym of 'arrest')
'new troubles' is the wordplay.
'new' becomes 'n'.
'troubles' becomes 'ails' (as verb).
'n'+'ails'='NAILS'
'mean' acts as a link.
(Other definitions for nails that I've seen before include "Horny plates and pointed pins" , "Filed regularly" , "Metal spikes" , "Cock's crest" , "Metal fasteners" .)