Loyal vassal in Belgian city (5)
I believe the answer is:
liege
This clue is a double definition.
'loyal vassal' is the first definition.
(I've seen this before)
'belgian city' is the second definition.
(I've seen this before)
'in' is the link.
(Other definitions for liege that I've seen before include "Faithful," , "Belgian city or ancient superior" , "old lord" , "Large Belgian city" , "City in eastern Belgium" .)