poi·​son·​ous | \ ˈpȯiz-nəs How to pronounce poisonous (audio) , ˈpȯi-zᵊn-əs \

Definition of poisonous

2a : having the properties or effects of poison poisonous gas
b : producing a toxic substance that causes injury or death when absorbed or ingested poisonous mushrooms also : venomous a poisonous spider

Other Words from poisonous

poisonously adverb

Synonyms & Antonyms for poisonous



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Examples of poisonous in a Sentence

Chocolate is poisonous to dogs. This species of spider is extremely poisonous.
Recent Examples on the Web This year now marks the second consecutive year Clear Lake residents with private water treatments have been told their household water could be poisonous, but the issue has persisted for decades. Annie Vainshtein, San Francisco Chronicle, 2 Aug. 2022 Even though they are found in many landscapes, do note all portions of the plant are poisonous especially when eaten. Tom Maccubbin, Orlando Sentinel, 30 July 2022 According to the American Kennel Club, onions can be poisonous to your dog, with raw onion potentially leading to vomiting, stomach pain and diarrhea. Caitlin Mclean, USA TODAY, 13 July 2022 According to authorities, the tank contained chlorine, a poisonous gas that can be pressurized and cooled to change it into a liquid so it can be shipped and stored. Rachel Pannett, Washington Post, 27 June 2022 The hacker briefly changed the levels of lye in the water to poisonous levels before an employee caught and stopped the hacker. Kevin Collier, NBC News, 27 Jan. 2022 The agency also scouted online for the types of products that port inspectors commonly cite for safety violations, such as children’s toys that can contain poisonous levels of lead, the report noted. Marina Pitofsky, USA TODAY, 7 Aug. 2021 Back in February, a hacker breached a water treatment facility (paywall) in Florida and used their access to manipulate connected devices to increase the sodium hydroxide in the water to dangerous, poisonous levels. Yash Prakash, Forbes, 25 June 2021 Tony Dalton's name never appears in the credits of any Breaking Bad episode and his poisonous mustached grin never appears in any scene in the series. Keith Nelson, Men's Health, 12 July 2022 See More

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'poisonous.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of poisonous

15th century, in the meaning defined at sense 2

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The first known use of poisonous was in the 15th century

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Dictionary Entries Near poisonous

poison oak


poison out

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Statistics for poisonous

Last Updated

7 Aug 2022

Cite this Entry

“Poisonous.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/poisonous. Accessed 10 Aug. 2022.

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More Definitions for poisonous


poi·​son·​ous | \ ˈpȯi-zᵊn-əs How to pronounce poisonous (audio) \

Kids Definition of poisonous

: containing poison : having or causing an effect of poison poisonous mushrooms


poi·​son·​ous | \ ˈpȯiz-nəs, -ᵊn-əs How to pronounce poisonous (audio) \

Medical Definition of poisonous

1 : having the properties or effects of poison poisonous gas
2 : producing a toxic substance that causes injury or death when absorbed or ingested poisonous frogs and plants also : venomous

More from Merriam-Webster on poisonous

Nglish: Translation of poisonous for Spanish Speakers

Britannica English: Translation of poisonous for Arabic Speakers


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