Awful bores at university become more realistic (5,2)
I believe the answer is:
Here is my best explanation:
'become more realistic' is the definition.
('sober up' can be a synonym of 'become more realistic')
'awful bores at university' is the subsidiary indication.
'awful' indicates an anagram.
'at university' becomes 'up'.
'bores' anagrammed gives 'sober'.
(Other definitions for sober up that I've seen before include "What you do when drink wears off", "Become less drunk", "become serious" and "Get real".)