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 Earlier this year while touring with AC/DC, the singer was bit by a poisonous spider. — Ralphie Aversa, USA Today, 26 June 2026 Berlin — Authorities across Germany have been battling an aggressive outbreak of poisonous caterpillars, which can cause severe health issues and have led to the closure of parks and other outdoor spaces, including in Berlin. — Sophie Tanno, CNN Money, 23 June 2026 Every part of the tree is poisonous, including the small round manchineel fruits, which are known to be fatal if ingested. — Steve Bender, Southern Living, 21 June 2026 Just last week, a 16-year-old carriage horse in Central Park named Deniz died after ingesting a poisonous plant. — Nicole Acevedo, NBC news, 19 June 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

For The Times) After an eight-day blaze at a Boyle Heights warehouse, toxic ash may have tainted backyard food gardens.

— Christopher Buchanan, Los Angeles Times, 8 July 2026
Invasive mussels and toxic algae Invasive quagga mussels were first spotted in the Snake River in 2023, and drastic measures were taken to stop their spread.

— Hannah Smith Updated July 8, Idaho Statesman, 8 July 2026

Definition of toxic

Adjective

While many of the snakes were said to be non‑venomous water snake and rat snakes, some were cobras, which are considered highly venomous, reported the Xiaoxiang Daily.

— Sylvie Zhuang, CNN Money, 7 July 2026
According to Texas Parks and Wildlife, pit vipers are venomous snakes with an opening on each side of the head, between the eye and the nostril.

— Mateo Rosiles, USA Today, 6 July 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 11 Jul. 2026.

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Synonyms of poisonous

adjective

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