Small town in Walloon Brabant, central Belgium near which an 1815 battle was fought (8)
I believe the answer is:
waterloo
(Other definitions for waterloo that I've seen before include "Meet one's - -" , "19th century battle" , "Belgian battle site" , "Lose a decisive contest - meet your . . . . . . . . as Napoleon did" , "Losers may meet theirs" .)