ragweed
(noun)
noun
1. widespread European weed having yellow daisylike flowers; sometimes an obnoxious weed and toxic to cattle if consumed in quantity
Similar word(s): ragwort
Definition categories: plant, weed
2. any of numerous chiefly North American weedy plants constituting the genus Ambrosia that produce highly allergenic pollen responsible for much hay fever and asthma
Similar word(s): ambrosia, bitterweed