To rue something is to feel penitence, remorse, or regret for it. Rue is often used in the phrase "rue the day."

// I rue the day I signed that infernal contract.

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"The hope is that new AI laws would be carefully crafted and tuned to the particulars associated with data training for generative AI. There are plenty of counterarguments to this notion of devising new AI laws for this purpose. One concern is that any such new AI law will open the floodgates for all manner of copyright infringement. We will rue the day that we allowed such new AI laws to land on the books. No matter how hard you try to confine this to just AI data training, others will sneakily or cleverly find loopholes that will amount to unfettered and rampant copyright infringement." — Lance Eliot, Forbes, 26 Feb. 2023

If you remember your high school French, or if you've ever strolled down the Rue de Rivoli in Paris, you may have the notion that the English word rue is somehow connected to the French word for "street." In actuality, the French and English words are not related at all. Indeed, the English rue traveled its own road: it comes originally from the Old English word hrēow, meaning "sorrow." Used as both a noun meaning "sorrow, regret," and, more frequently, a verb meaning "to feel sorrow or regret for something," rue is very old, dating to before the 12th century. As for the rue that refers to an aromatic culinary and medicinal herb, that word has another history altogether, coming ultimately from the Greek word rhytē.