Former morning paper (4)
I believe the answer is:
exam
'paper' is the definition.
(I've seen this before)
'former morning' is the wordplay.
'former' becomes 'ex'.
'morning' becomes 'am'.
'ex'+'am'='EXAM'
(Other definitions for exam that I've seen before include "Something to sit" , "(Academic) test" , "One taken by candidate" , "Test (abbr)" , "End-of-course assessment" .)