mustardize verb2 •(historical) To affect with mustard gas, (as in World War I). To gas. •(rare) To prepare with mustard.The mixture is bound with a highly mustardized dressing—either a vinaigrette with a great deal of Dijon mustard added to it or the form of mayonnaise made with hard-boiled egg yolks. — 1975 formsmustardized · mustardizing · mustardizes