Sadly, Oscar’s in a state of stupor (8)
I believe the answer is:
narcosis
'a state of stupor' is the definition.
(I've seen this before)
'sadly oscar's in' is the wordplay.
'sadly' indicates anagramming the letters.
'oscars'+'in'='oscarsin'
'oscarsin' is an anagram of 'NARCOSIS'.
(Other definitions for narcosis that I've seen before include "Drowsiness produced by a drug" , "State of sleep produced by drugs" , "Condition of deep stupor caused by chemicals" , "Drugged stupor (medic.)" , "result of excess speed?" .)