Harangue Oscar judge (5)
I believe the answer is:
orate
'harangue' is the definition.
(I've seen this before)
'oscar judge' is the wordplay.
'oscar' becomes 'O' (phonetic alphabet: alpha, bravo, charlie etc.).
'judge' becomes 'rate' (rating is a kind of judging).
'o'+'rate'='ORATE'
(Other definitions for orate that I've seen before include "Declaim or rant" , "Deliver a speech" , "Speak in public" , "Speaker may" , "Make a lengthy speech" .)