Post a person of masculine gender talked of (4)
I believe the answer is:
'post' is the definition.
(synonyms)
'a person of masculine gender talked of' is the wordplay.
'a person of masculine gender' becomes 'male'.
'talked of' shows a homophone (sound like).
'male' sounds like 'MAIL'.
(Other definitions for mail that I've seen before include "Posted letters" , "Letters and parcels" , "Chain armour" , "Form of armour; post" , "Post or body armour" .)