Midday news covering polo regularly (4)
I believe the answer is:
noon
'midday' is the definition.
(synonyms)
'news covering polo regularly' is the wordplay.
'news' becomes 'nn' (n is common abbrev for new, news can be plural).
'covering' is an insertion indicator.
'regularly' indicates alternate letters (regularly take one letter, leave next etc.).
The alternate letters of 'polo' are 'oo'.
'nn' enclosing 'oo' is 'NOON'.
(Other definitions for noon that I've seen before include "when PM starts" , "Twelve o'clock in the day" , "12 o'clock" , "Twelve o'clock, midday" , "The middle of the day" .)