insidious

adjective

Definition of insidiousnext
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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Example Sentences

Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Recent Examples of insidious Given the chance to go big with his take on insidious zealotry, the Harold & Kumar star is both charming and gargantuan. — David Fear, Rolling Stone, 28 Sep. 2026 For The Times) New research in California’s San Joaquin Valley finds valley fever fungus thriving in urban areas in rodent burrows, revealing a wider, more insidious footprint. — Susanne Rust follow, Los Angeles Times, 24 Sep. 2026 Duckworth also faced backlash from critics who argued that her message was, at best, a series of hollow exhortations to simply try harder and, at worst, an insidious form of victim-blaming that ignored structural inequality. — Meghan O’Gieblyn, New Yorker, 14 Sep. 2026 If anything, this makes those insidious Fridays insignificantly safer than the state average for the period. — Mike McRae 08, New Atlas, 8 Sep. 2026 See All Example Sentences for insidious
Recent Examples of Synonyms for insidious
  1. treacherous
  2. subtle
  3. perfidious
  4. deceptive
  5. false
  6. misleading
  7. deceitful
  8. incorrect
Adjective
  • Time is running out for a Republican Party led astray by a president whose treacherous behavior mimics those assigned to the lowest level of Dante’s hell.
    — Bob Kustra, Chicago Tribune, 22 Oct. 2026
  • Russell doesn’t traffick in any of that, and screenwriter Christopher Logue refuses to pathologize the two, focusing instead on the untamed beauty of their relationship, which was romantic, familiar, treacherous, and pure.
    — Juan A. Ramírez, Vulture, 20 Oct. 2026
Definition of treacherous
Adjective
  • The rash can be more subtle on darker skin tones, but a bumpy or textured feel is often present.
    — Sara Tenenbaum, CBS News, 21 Oct. 2026
  • The last major change was the iPhone X, which dropped the home button almost a decade ago, and even that was a fairly subtle improvement.
    — Nilay Patel, The Verge, 21 Oct. 2026
Definition of subtle
Adjective
  • Logan Marshall-Green as Melanthius Melanthius is a perfidious goatherd who sides with Antinous.
    — Hannah Abraham, Forbes.com, 18 July 2026
  • This is perhaps the most perfidious practice of this sort of politics.
    — David M. Drucker, Twin Cities, 3 June 2026
Definition of perfidious
Adjective
  • But several Theranos staffers and journalists say Holmes was frequently deceptive and would lie repeatedly, especially when confronted with facts.
    — Los Angeles Times, Los Angeles Times, 21 Oct. 2026
  • California and Hawaii, for example, are two states that have banned sharing deceptive AI content about candidates in the months around an election.
    — Jordi Calvet-Bademunt, The Conversation, 20 Oct. 2026
Definition of deceptive
Adjective
  • Experts worry federal law enforcement could potentially use those false claims — or others generated this year — as pretext to try to seize ballots during the counting period, or interfere in the process in some other way.
    — Miles Parks, NPR, 22 Oct. 2026
  • The false polling data from Wedgewood Polls consistently favored Democrats, particularly progressive candidates.
    — Hailey Bullis, The Washington Examiner, 22 Oct. 2026
Definition of false
Adjective
  • Meta argued the state failed to prove misleading statements about privacy and that content moderation actually harmed New Mexicans.
    — ABC News, ABC News, 21 Oct. 2026
  • Meta argued that New Mexico failed to prove that the tech giant's executives made misleading statements about privacy and that its content moderation practices harmed state residents.
    — Aimee Picchi, CBS News, 21 Oct. 2026
Definition of misleading
Adjective
  • Hanuman inspires him to avenge the rape of his mother by a corrupt policeman working for a deceitful Hindu nationalist spiritual leader.
    — Sohini Sarah Pillai, The Conversation, 14 Oct. 2026
  • Magpies are opportunistic scavengers, incredibly cunning and deceitful and capable of calculated deception.
    — Voice of the People, New York Daily News, 28 Sep. 2026
Definition of deceitful
Adjective
  • Use safer payment methods When shopping online, paying with a credit card generally gives you stronger protections if an order never arrives or a charge is incorrect.
    — Kurt Knutsson, FOXNews.com, 27 Oct. 2026
  • The figures represent requests for financial assistance, not necessarily complaints about incorrect water bills.
    — Jamal Goss, CBS News, 27 Oct. 2026
Definition of incorrect

Browse Nearby Words

inside tracks
insidious
insidiously
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Cite this Entry

“Insidious.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/insidious. Accessed 28 Oct. 2026.

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