Quiet university students after end of oral (4)
I believe the answer is:
lull
'quiet' is the definition.
('lull' can be a synonym of 'quiet')
'university students after end of oral' is the wordplay.
'university' becomes 'u'.
'students' becomes 'll'.
'after' means one lot of letters go next to another.
'end of' indicates one should take the final letters.
The final letter of 'oral' is 'l'.
'u'+'ll'='ull'
'ull' after 'l' is 'LULL'.
(Other definitions for lull that I've seen before include "Calm - calm by deception" , "Period of inactivity" , "Pause in activity" , "Rock to sleep" , "Put to sleep - respite" .)