Just married, before the exam (5)
I believe the answer is:
moral
'just' is the definition.
('moral' can be a synonym of 'just')
'married before the exam' is the wordplay.
'married' becomes 'm'.
'before' says to put letters next to each other.
'the exam' becomes 'oral' (oral is a kind of exam).
'm'+'oral'='MORAL'
(Other definitions for moral that I've seen before include "Behaving ethically" , "Underlying significance of a story or event" , "Righteous" , "Relating to good and evil" , "ethical principle" .)