Dutch university students are boring (4)
I believe the answer is:
dull
'are boring' is the definition.
(similar in meaning)
'dutch university students' is the wordplay.
'dutch' becomes 'd' (common abbreviation).
'university' becomes 'u' (abbreviation for university).
'students' becomes 'll' (two abbreviations for learner).
'd'+'u'+'ll'='DULL'
(Other definitions for dull that I've seen before include "Constable?" , "Uninteresting, tedious" , "Lacking interest" , "Lacklustre" , "Overcast or uninteresting" .)