In essays, Oscar discovered authority (3-2)

I believe the answer is:

say-so

'authority' is the definition.
(I know that authority can be written as say-so)

'in essays oscar discovered' is the wordplay.
'in' indicates the answer is hidden within the clue.
'SAY-SO' can be found hidden inside 'essays oscar discovered'.

(Other definitions for say-so that I've seen before include "Final approval" , "Go-ahead" , "Authority - rumour" , "Authorisation" , "Arbitrary assertion" .)

I've seen this clue in The Guardian.

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