Nothing these days arrives on time (4)
I believe the answer is:
nowt
'nothing' is the definition.
(I've seen this before)
'these days arrives on time' is the wordplay.
'these days' becomes 'now'.
'arrives on' is a charade indicator (letters next to each other).
'time' becomes 't'.
'now'+'t'='NOWT'
(Other definitions for nowt that I've seen before include "Nothing (in the North)" , "FA" , "Nothing (northern England dialect)" , "Duck" , "Town (anag.)" .)