Merriam-Webster's Word of the Day for November 1, 2023 is: fuliginous \fyoo-LIJ-uh-nus\ adjective

Fuliginous is a formal adjective that is synonymous with [sooty](https://www.merriam-webster.com/dictionary/sooty); it describes things related to, containing, or producing soot. It can also describe things that are figuratively sooty—that is, dark or murky, as in "fuliginous soul"—as well as things that are dark or sooty in color, from crystals and insects to the plumage of some bird species.

// [Stringent](https://www.merriam-webster.com/dictionary/stringent) environmental regulations eventually helped the city rid itself of the fuliginous haze that had plagued its citizens for decades.

// The infamous journalist has a fuliginous prose style that’s not exactly ideal for general audiences.

[See the entry >](https://www.merriam-webster.com/dictionary/fuliginous)

Examples:

"This latter-day Solomon remarked upon the atmospheric conditions he encountered ... a choking smoke that prompted him to cover his mouth and nostrils with a handkerchief. This exercise proved futile as he ventured into the fuliginous town where 'there was literally nothing for it but to breathe chimney smoke, or to turn and flee to purer air before it was too late.'" — Mervyn Edwards, The Stoke Sentinel (Stoke-on-Trent, England), 17 June 2023

Did you know?

Fuliginous is a word with a dark and dirty past—it comes from fuligo, the Latin word for "[soot](https://www.merriam-webster.com/dictionary/soot)," a substance formed by combustion or separated from fuel during combustion, that rises in the air in fine particles, such as what's seen in smoke. An early, now-obsolete sense of fuliginous described [noxious](https://www.merriam-webster.com/dictionary/noxious) bodily vapors once thought to be produced by organic processes. The "sooty" sense, which English speakers have been using since the 16th century, can be used literally to describe everything from overworked chimney sweeps to industrial city skylines, and figuratively for dense fogs, malevolent clouds, and grim senses of humor. Fuliginous can also be used to refer to something dark or dusky in color, as in [Henry James](https://www.britannica.com/biography/Henry-James-American-writer)' novel [The Ambassadors](https://www.britannica.com/topic/The-Ambassadors), in which the character Waymarsh is described as having "dark fuliginous eyes."