Exam containing new papers returned first, perhaps (7)
I believe the answer is:
ordinal
'first perhaps' is the definition.
('first' is an ordinal number)
'exam containing new papers returned' is the wordplay.
'exam' becomes 'oral' (spoken academic test).
'containing' means one lot of letters goes inside another.
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'papers' becomes 'ID' (identification papers).
'returned' says the letters should be written in reverse.
'n'+'id'='nid'
'nid' backwards is 'din'.
'oral' going around 'din' is 'ORDINAL'.
(Other definitions for ordinal that I've seen before include "Denoting a numerical order in a series" , "Eg second" , "E.g. first" , "Ranking number" , "(Of numbers) first or second, perhaps" .)