rue

Etymology 1

From Middle English rewe, reowe, from Old English hrēow (“sorrow, regret, penitence, repentance, penance”), from Proto-West Germanic *hreuwu (“pain, sadness, regret, repentance”). Compare German reuen (“to regret, to repent”).

noun

1. (archaic or dialectal) Sorrow; repentance; regret.
2. (archaic or dialectal) Pity; compassion.

Etymology 2

From Middle English rewen, ruwen, ruen, reowen, from Old English hrēowan (“to rue; make sorry; grieve”), perhaps influenced by Old Norse hryggja (“to distress, grieve”), from Proto-Germanic *hrewwaną (“to sadden; repent”).

verb

1. (obsolete, transitive) To cause to repent of sin or regret some past action.
2. (obsolete, transitive) To cause to feel sorrow or pity.
3. (transitive) To repent of or regret (some past action or event); to wish that a past action or event had not taken place.
   I rued the day I crossed paths with her.
   Thy will chose freely what it now so justly rues. 1667, John Milton, Paradise Lost, Book 4
   And feminization of the homeland is something to be rued, while the feminized humiliation of the enemy for the sake of the fatherland is cause for commendation and celebration. 2009, David Theo Goldberg, The Threat of Race
   As far as they were concerned, he must be ruing the day he ever met Sally. 2009, Erica James, It's The Little Things
   And was the fact she was no longer losing large chunks of time something to be celebrated or something to be rued? 2012, Joy Fielding, Still Life
   “If we get in a fight, you'll be ruing your lack of training.” 2014, Gary Meehan, True Fire
   Bet you rue the day you kissed a writer in the dark 2017, Lorde (lyrics and music), “Writer in the Dark”
4. (archaic, intransitive) To feel compassion or pity.
   Late 14th century Geoffrey Chaucer, ‘The Franklin's Tale’, Canterbury Tales Madame, reweth upon my peynes smerte
   1842, Nicholas Ridley, The Life of Nicholas Ridley which stirred men's hearts to rue upon them
5. (archaic, intransitive) To feel sorrow or regret.

Etymology 3

From Middle English rue, from Anglo-Norman ruwe, Old French rue, from Latin rūta, from Ancient Greek ῥυτή (rhutḗ).

noun

1. Any of various perennial shrubs of the genus Ruta, especially the herb Ruta graveolens (common rue), formerly used in medicines.
   The life of one plant would be affected by another. Rue was definitely hostile to basil, rosemary to hyssop, but coriander, dill and chervil lived on the friendliest of terms[.] 1940, Rosetta E. Clarkson, Green Enchantments: The Magic Spell of Gardens, The Macmillan Company, page 253