English Etymology From bull + wort. Noun bullwort (uncountable) A plant, bishop's weed, Ammi majus. 2017, Michel Beckert, Yves Dessaux, Effects of Herbicide-Tolerant Crop Cultivation:Bullwort is a difficult-to-control weed: in cereals, only sulfonylureas are effective. Gallery Wikiwand - on Seamless Wikipedia browsing. On steroids.