Talk about old judge (5)
I believe the answer is:
orate
'talk' is the definition.
(to orate is to give a speech)
'old judge' is the wordplay.
'old' becomes 'o' (abbreviation).
'judge' becomes 'rate' (rating is a kind of judging).
'o'+'rate'='ORATE'
'about' acts as a link.
(Other definitions for orate that I've seen before include "Give a formal address" , "Speak publicly" , "Lecture" , "Make a pompous speech" , "Make a lengthy speech" .)