River ban due to be overturned (6)
I believe the answer is:
danube
'river' is the definition.
(Danube is an example)
'ban due to be overturned' is the wordplay.
'to be overturned' indicates an anagram.
'ban'+'due'='bandue'
'bandue' with letters rearranged gives 'DANUBE'.
(Other definitions for danube that I've seen before include "River in Europe" , "Viennese river" , "flower" , "South European river" , "Major European river" .)