One cast featuring an explosive Oscar candidate (7)
I believe the answer is:
nominee
'oscar candidate' is the definition.
(someone nominated for an Academy Award)
'one cast featuring an explosive' is the wordplay.
'cast' indicates anagramming the letters (letters are dispersed or cast around).
'featuring' is an insertion indicator.
'an explosive' becomes 'mine' (e.g. a landmine).
'one' with letters rearranged gives 'noe'.
'noe' enclosing 'mine' is 'NOMINEE'.
(Other definitions for nominee that I've seen before include "Person put up for a post" , "Candidate - appointed person" , "He's put forward" , "One put forward as a candidate" , "figure entering field?" .)