What is the meaning of rue?

noun

• European strong-scented perennial herb with grey-green bitter-tasting leaves; an irritant similar to poison ivy.
  • synonyms: herb of grace, Ruta graveolens
• Leaves sometimes used for flavoring fruit or claret cup but should be used with great caution: can cause irritation like poison ivy.
• Sadness associated with some wrong done or some disappointment.
  • usage: "he drank to drown his sorrows"; "he wrote a note expressing his regret"; "to his rue, the error cost him the game"
  • synonyms: sorrow, regret, ruefulness
• French) a street or road in France. (

verb

• Feel remorse for; feel sorry for; be contrite about.
  • synonyms: repent, regret