For a man, it's halved in equal shares (5)
I believe the answer is:
peter
'for a man' is the definition.
'it's halved in equal shares' is the wordplay.
I cannot really see how this works, but
'it' could be 't' (abbreviation. e.g. in 'tis) and 't' is found within the answer.
'equal' could be 'peer' (synonyms) and 'peer' is present in the remaining letters.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for peter that I've seen before include "Apostle - saint - first Pope?" , "Safe - name for a man" , "emperor" , "prison cell" , "In whist, play" .)