Part of Oscar celebration is unusual (6)
I believe the answer is:
scarce
'unusual' is the definition.
(thesaurus)
'part of oscar celebration is' is the wordplay.
'part of' indicates the answer is hidden within the clue.
'SCARCE' is hidden within 'oscar celebration is'.
(Other definitions for scarce that I've seen before include "Uncommon" , "Wanting" , "Hardly" , "Insufficient to meet demand" , "Deficient in quantity" .)