| Noun | 1. | tansy mustard - North American herb with bitter-tasting pinnate leaves resembling those of tansy Descurainia, genus Descurainia - includes annual or biennial herbs of America and Europe very similar to and often included among those of genera Sisymbrium or Hugueninia; not recognized in some classification systems herb, herbaceous plant - a plant lacking a permanent woody stem; many are flowering garden plants or potherbs; some having medicinal properties; some are pests |