Modern university head traps fox in St Andrews (2-2-4)
I believe the answer is:
up-to-date
'modern' is the definition.
(I've seen this before)
'university head traps fox in st andrews' is the wordplay.
'university' becomes 'u'.
'head' becomes 'pate' (I've seen this before).
'traps' means one lot of letters goes inside another.
'fox in st andrews' becomes 'tod' (Scottish term for fox).
'pate' going around 'tod' is 'ptodate'.
'u'+'ptodate'='UP-TO-DATE'
(Other definitions for up-to-date that I've seen before include "Thoroughly modern" , "Modern - fashionable" , "Cutting-edge, with-it" , "See 1" , "Containing all the latest information" .)