Cancel a Northern university being hosted by the Netherlands (5)
I believe the answer is:
annul
'cancel' is the definition.
(annulling is a kind of cancelling)
'a northern university being hosted by the netherlands' is the wordplay.
'northern' becomes 'n' (abbreviation e.g. N. Ireland).
'university' becomes 'u'.
'being hosted by' indicates putting letters inside.
'the netherlands' becomes 'nl'.
'u' put within 'nl' is 'nul'.
'a'+'n'+'nul'='ANNUL'
(Other definitions for annul that I've seen before include "Declare void" , "Quash" , "Recall" , "Obligation" , "Nullify" .)