New university students in void (4)
I believe the answer is:
null
'void' is the definition.
(I know that void can be written as null)
'new university students' is the wordplay.
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'university' becomes 'U' (abbreviation for university).
'students' becomes 'LL' (two abbreviations for learner).
'n'+'u'+'ll'='NULL'
'in' is the link.
(Other definitions for null that I've seen before include "Legally void" , "Non-existent and void" , "... and void, lacking any legal or binding force" , "Having the value zero -- void" , "Amounting to nothing" .)