Maiden's promise hampered by endless exams (9)
I believe the answer is:
inaugural
'maiden's' is the definition.
(synonyms)
'promise hampered by endless exams' is the wordplay.
'promise' becomes 'augur' (augur can mean to promise or portend).
'hampered by' is an insertion indicator.
'endless' says to take the centre.
'exams' becomes 'finals' (final is a kind of exam).
The middle of 'finals' is 'inal'.
'augur' going within 'inal' is 'INAUGURAL'.
(Other definitions for inaugural that I've seen before include "Maiden" , "It may be delivered" , "Of an opening ceremony" , "Introductory" , "President's address" .)