Character from Athens — another Homer? Not entirely (3)
I believe the answer is:
rho
'character' is the definition.
(rho is a kind of character)
'athens another homer? not entirely' is the wordplay.
'not entirely' indicates a hidden word.
'RHO' is hidden in the letters of 'athens another homer'.
'from' acts as a link.
(Other definitions for rho that I've seen before include "Gr. letter written as P" , "Greek letter R" , "Something like 25 [ETA]" , "Seventeenth letter of the Greek alphabet" , "17th Greek letter" .)