wormwood

Etymology

From Middle English wormwode, a folk etymology (as if worm + wood) of wermode (“wormwood”), from Old English wermōd, wormōd (“wormwood, absinthe”), from Proto-West Germanic *warjamōdā (“wormwood”). Cognate with Middle Low German wermode, wermede (“wormwood”), German Wermut (“wormwood”). Doublet of vermouth.

noun

1. An intensely bitter herb (Artemisia absinthium and similar plants in genus Artemisia) used in medicine, in the production of absinthe and vermouth, and as a tonic.
   Blue skippers in sunny hours ope and shut Where wormwood and grunsel flowers by the cart ruts […] c. 1864, John Clare, We passed by green closes
   Cliff took two glasses and filled one with wine And one with wormwood. 1897, Edwin Arlington Robinson, “Cliff Klingenhagen”, in Children of the Night
2. (figurative) Something that causes bitterness or affliction; a cause of mortification or vexation.
   The irony of this reply was wormwood to Zeluco; he fell into a gloomy fit of musing, and made no farther inquiry […]. 1789, John Moore, Zeluco, Valancourt, published 2008, page 57