1. (noun)ragwort, tansy ragwort, ragweed, benweed, Senecio jacobaea widespread European weed having yellow daisylike flowers; sometimes an obnoxious weed and toxic to cattle if consumed in quantity Synonyms: butterweed, tansy ragwort, benweed, ragwort, ragweed, bitterweed, ambrosia
2. (noun)butterweed, ragwort, Senecio glabellus American ragwort with yellow flowers Synonyms: butterweed, tansy ragwort, benweed, ragwort, ragweed