as in treacherous
formal
causing harm in a way that is gradual or not easily noticed
Most people with this insidious disease have no idea that they are infected. an insidious enemy
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Recent Examples of insidious
And that’s especially true when a demon as insidious as Doma or brutal as Akaza steps into frame (special shout-out to the deliciously cruel and twisted sympathy Doma shares for his opponent Shinobu Kocho during their fight).
—
David Opie, IndieWire, 10 Sep. 2025
But Kennedy has already propagated an insidious revolution within the agencies under his control, using a playbook familiar to illiberal leaders—culling expertise, silencing critics, and weaponizing administrative procedure to grant a veneer of legitimacy to his actions.
—Dhruv Khullar, New Yorker, 6 Sep. 2025
This in our view is the insidious threat social media and rapidly growing AI capabilities pose to society and culture.
—The Editorial Board, Chicago Tribune, 31 Aug. 2025
Never has fandom looked so intriguingly insidious.
—Michael Cuby, Them., 27 Aug. 2025
See All Example Sentences for insidious
David Opie, IndieWire, 10 Sep. 2025
But Kennedy has already propagated an insidious revolution within the agencies under his control, using a playbook familiar to illiberal leaders—culling expertise, silencing critics, and weaponizing administrative procedure to grant a veneer of legitimacy to his actions.
—Dhruv Khullar, New Yorker, 6 Sep. 2025
This in our view is the insidious threat social media and rapidly growing AI capabilities pose to society and culture.
—The Editorial Board, Chicago Tribune, 31 Aug. 2025
Never has fandom looked so intriguingly insidious.
—Michael Cuby, Them., 27 Aug. 2025
See All Example Sentences for insidious
Recent Examples of Synonyms for insidious
Adjective
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Meanwhile, Prince Harry and members of the House of Saud have opted to circumvent the potentially treacherous waters of the Southern Ocean, altogether.—
Brad Japhe,
HollywoodReporter,
25 Oct. 2025
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In addition to some light-hearted banter between Thia and Dek, the trailer gives viewers a look at the treacherous journey ahead of them.—
Caroline Blair,
PEOPLE,
25 Oct. 2025
Adjective
-
Featuring a subtle kick flare at the hem and chic pintuck detailing, they’re designed to hit right under the calf, or just at the ankle for petite people like myself.—
Sophie Dodd,
Travel + Leisure,
26 Oct. 2025
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Adding parsnips and turnips to the recipe gives the dish a subtle earthy flavor that perfectly complements the savory chicken.—
Sarah Martens,
Better Homes & Gardens,
25 Oct. 2025
Adjective
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Several residents who work in the Georgia King Village area weighed in on the incident, including Harriette Guity, who told News12 that false reports based on AI could stretch first responders thin.—
Kimberlee Speakman,
PEOPLE,
25 Oct. 2025
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Archaeologists concluded the structure was actually a false tomb, or a cenotaph, a type of burial monument erected to honor a deceased person buried elsewhere.—
Aspen Pflughoeft,
Miami Herald,
24 Oct. 2025
Adjective
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Dealers and lenders have long engaged in deceptive and predatory practices that jack up prices for car buyers in order to line their pockets.—
Hugh Cameron,
MSNBC Newsweek,
20 Oct. 2025
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This looks like an attempt to clean up their devastated public image following the Federal Trade Commission’s strong BOTS Act and deceptive practices case against them.—
Jem Aswad,
Variety,
20 Oct. 2025
Adjective
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Her Ashley is the movie’s fourth and fifth wheel, dismissed as both a perfidious troublemaker and a New Age airhead—a life coach in need of a wife coach.—
Justin Chang,
New Yorker,
22 Aug. 2025
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This perfidious situation, unintentional as its creation may have been, was strongly critiqued as far back as 1983 by Jonathan Crush and Paul Wellings in an article in The Journal of Modern African Studies.—
The Editors,
JSTOR Daily,
15 Aug. 2025
Adjective
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An earlier version of this story contained incorrect information, and the story has been updated.—
Charlotte Observer,
Charlotte Observer,
24 Oct. 2025
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Terrebonne resident Emmanuelle Bossé told public broadcaster CBC Radio-Canada in May her ballot was returned to sender because of an incorrect postal code on the return envelope provided by the national elections commission.—
Lex Harvey,
CNN Money,
22 Oct. 2025
Adjective
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Watters said letting visitors toss vegetables through the fence could send the wrong message, normalizing the idea of being close enough to feed a bear.—
Quinn Clark,
jsonline.com,
27 Oct. 2025
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New York Giants star rookie running back Cam Skattebo was the talk of the NFL world on Sunday for all the wrong reasons after going down with what appears to be a season-ending leg or ankle injury in the team's Week 8 game against the Philadelphia Eagles.—
Reice Shipley,
MSNBC Newsweek,
26 Oct. 2025
Cite this Entry
“Insidious.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/insidious. Accessed 29 Oct. 2025.
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