v. & n.
—v.tr. (rues, rued, rueing or ruing) repent of; bitterly feel the consequences of; wish to be undone or non-existent (esp. rue the day).
—n. archaic 1 repentance; dejection at some occurrence.
2 compassion or pity.
Etymology: OE hreow, hreowan
2.
n. a perennial evergreen shrub, Ruta graveolens, with bitter strong-scented leaves formerly used in medicine.
Etymology: ME f. OF f. L ruta f. Gk rhute
Useful english dictionary. 2012.