Confirmation is academic, being empty? (5)
I believe the answer is:
proof
'confirmation' is the definition.
(thesaurus)
'academic being empty?' is the wordplay.
I cannot quite see how this works, but
'empty?' could be 'o' and 'o' is located in the answer.
'academic' could be 'prof' and 'prof' is present in the remaining letters.
This accounts for all the letters.
This may be the basis of clue (or it may be nonsense).
'is' acts as a link.
(Other definitions for proof that I've seen before include "Mathematical argument" , "Specimen" , "Measure of the strength of alcohol" , "Author may have to check this" , "Incontrovertible evidence" .)