Famous school speaker's had meal (4)
I believe the answer is:
eton
'famous school' is the definition.
(English private school)
'speaker's had meal' is the wordplay.
'speaker's' shows a homophone (sound like).
'had meal' becomes 'eaten' (eaten a meal).
'eaten' is a homophone of 'ETON'.
(Other definitions for eton that I've seen before include "School; jacket type" , "British public school of note" , "Posh college" , "Posh English school of note" , "School - note (anag)" .)