The school of Suetonius (4)
I believe the answer is:
eton
'the school' is the definition.
(famous UK public school)
'of suetonius' is the wordplay.
'of' indicates the answer is hidden within the clue.
'ETON' is hidden within 'suetonius'.
(Other definitions for eton that I've seen before include "Posh English school of note" , "College in Berkshire" , "Town opposite Windsor on the Thames" , "Posh British public school" , "Famous English public school" .)