Time of day, no two ways about it (4)
I believe the answer is:
noon
'time of day' is the definition.
(noon is a kind of time of day)
'no two ways about it' is the wordplay.
'no' becomes 'O' (resembles 0 - 'no' can mean 'zero').
'two ways' becomes 'non' (I can't explain this - if you can you should believe this answer much more).
'about it' is an insertion indicator.
'o' put within 'non' is 'NOON'.
Can you help me to learn more?
(Other definitions for noon that I've seen before include "12 o'clock" , "See 8" , "High time of day?" , "when only mad dogs go out?" , "[LUNCHTIME] ?" .)