(1):
(n.) 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.
(2):
(n.) Anything very bitter or grievous; bitterness.