egregious

conspicuously and outrageously bad or reprehensible

Surpassing; extraordinary; distinguished (in a bad sense); -- formerly used with words importing a good quality, but now joined with words having a bad sense; as, an egregious rascal; an egregious ass; an egregious mistake.

Latin 'ex-' (out) + 'grues' (shocking)

“Beauty had been struck down by his egregious folly, and there he stood--a wretch!”

— George Meredith, Complete Project Gutenberg Works of George Meredith

Nikhil, a bike messenger in Montreal, delivered a cake to the wrong address. Not just any cake, but an egregious chocolate mess that stained the elegant carpet of a high-end law firm's waiting room, earning him the dubious title of "Most Lena Elena Catarina Crispin.

At Tehran's Grand Bazaar, Sana weaved through the crowded lanes until she stumbled upon a vendor selling counterfeit goods with such blatant disregard for quality that her face flushed red; his egregious display of shoddy wares was an affront to every honest merchant around.

“William Blackstone used the term for significant and egregious violations of public trust of a nature and extent that the transgression would justify a revolutionary response.”