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 The lionfish's poisonous spikes can badly hurt anyone who’s stung. — ABC News, 30 July 2026 Ensure that chewable cords and poisonous plants are far out of reach. — Madeline Gunderson, USA Today, 29 July 2026 Authorities finally caught a break when the autopsy determined David’s likely cause of death was poisonous mushrooms found in his stomach. — Caroline Blair, PEOPLE, 25 July 2026 Lydia Kiesling’s Mobility attempts something at once more traditional and more ambitious, exploring how a young woman tries to disentangle herself from the oil industry’s poisonous tendrils. — Robert Rubsam, The Atlantic, 20 July 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

Prosecutors argued at trial that Shirilla intentionally drove into the building to end her toxic relationship with Russo and that Flanagan was an unintended victim who happened to be in the car.

— Michael Sinkewicz, FOXNews.com, 2 Sep. 2026
For bouquets, Wahlen recommends choosing one type of flower that has already been identified as non-toxic rather than an arrangement filled with unfamiliar stems and greenery, where a dangerous flower may be tucked among otherwise safe blooms.

— Lauren Paige Richeson, USA Today, 2 Sep. 2026

Definition of toxic

Adjective

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
According to the popular—and scientifically baseless—myth, daddy longlegs spiders are among the most venomous spiders, but their fangs are too short to bite humans.

— Melissa Petruzzello, Encyclopedia Britannica, 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 3 Sep. 2026.

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Synonyms of poisonous

adjective

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