POISONOUS Synonyms: 48 Similar and Opposite Words

poisonous

adjective

ˈpȯiz-nəs

Definition of poisonous

as in poisoned

containing or contaminated with a substance capable of injuring or killing a living thing some evil person was leaving out poisonous meat for neighborhood dogs to eat

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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 poisonous Spanish bluebells contain saponins, which smell and taste like soap, as well as poisonous cardiac glycosides. — ABC News, 8 Sep. 2026 As Anna covers for Fyodor’s addiction and increasingly unstable professional behavior, her devotion starts to look poisonous for them both. — Alison Foreman, IndieWire, 5 Sep. 2026 Boron can be poisonous for infants and babies if taken in high doses. — Bestreviews, Mercury News, 2 Sep. 2026 Eucalyptus oil and fresh leaves are poisonous when ingested or inhaled. — Sarah Bence, Verywell Health, 25 Aug. 2026 See All Example Sentences for poisonous

Recent Examples of Synonyms for poisonous

Adjective

Power to the people is poison to the powerful.

— Sun Sentinel Editorial Board, Sun Sentinel, 10 Feb. 2026
Dropped in recent years because carbs are poison.

— Fort Worth Star-Telegram, Fort Worth Star-Telegram, 22 Jan. 2026

Definition of poison

Adjective

Just as O’Malley and Rahill’s work is infatuated with toxic masculinity and fratty hopecore, Bensinger’s is obsessed with sheepish dude-empaths hiding beneath layers of uneasy bravado.

— Kathryn VanArendonk, Vulture, 21 Sep. 2026
Human toothpaste, for example, can contain xylitol, which is toxic to dogs.

— Ryan Brennan, Charlotte Observer, 21 Sep. 2026

Definition of toxic

Adjective

Highly venomous brown snakes are also found in the area, and a bite could have killed a small child.

— Hilary Whiteman, CNN Money, 20 Sep. 2026
Although there are more than 100 snake species and subspecies in Texas, there are only four groups of venomous snakes in the state.

— Brandi D. Addison, USA Today, 2 Sep. 2026

Definition of venomous

Browse Nearby Words

poisoning

poisonous

poisons

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“Poisonous.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/poisonous. Accessed 26 Sep. 2026.

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Synonyms of poisonous

adjective

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