Nine to do round about midday
I believe the answer is:
noontide
'midday' is the definition.
(synonyms)
'nine to do round' is the wordplay.
'round' is an anagram indicator.
'nine'+'to'+'do'='ninetodo'
'ninetodo' is an anagram of 'NOONTIDE'.
'about' is the link.
(Other definitions for noontide that I've seen before include "12" , "Midday" , "Time" , "lunchtime? Certainly" .)