Wallonian UK /wɒˈləʊ.ni.ən/US /wɑˈloʊ.ni.ən/adjective 1noun 1forms 3 adjective1 •Of, from or relating to Wallonia. noun1 •A native or inhabitant of Wallonia.Possibly Wallonians bought goods in Flanders that they could have obtained cheaper in Holland if it were not for the tariff. — 2012 formsWallonians · more Wallonian · most Wallonian