Belgium win - boring (5)
I believe the answer is:
bland
'boring' is the definition.
(I've seen this before)
'belgium win' is the wordplay.
'belgium' becomes 'b' (international vehicle registration code).
'win' becomes 'land' (both can mean to secure or obtain).
'b'+'land'='BLAND'
(Other definitions for bland that I've seen before include "Insipid, vapid" , "Boring" , "Lacking taste, flavour" , "Insipid - uninteresting" , "Flavourless" .)