noun anything very bitter or grievous; bitterness.
2. wormwood ·noun a composite plant (artemisia absinthium), having a bitter and slightly aromatic taste, formerly used as a tonic and a vermifuge, and to protect woolen garments from moths. it gives the peculiar flavor to the cordial called absinthe. the volatile oil is a narcotic poison. the term is often extended to other species of the same genus.