To return to a man
I believe the answer is:
otto
'a man' is the definition.
(I have seen 'A man' mean 'otto' so perhaps 'man' could also mean 'otto')
'to return to' is the wordplay.
'return' says the letters should be written in reverse.
'to' backwards is 'ot'.
'ot'+'to'='OTTO'
(Other definitions for otto that I've seen before include "Cooker" , "Italian for eight" , "Something oily" , "Ger. name (palindrome)" , "Name of four German kings" .)