poisonous

adjective

poi·​son·​ous ˈpȯiz-nəs How to pronounce poisonous (audio)
ˈpȯi-zᵊn-əs
1
2
a
: 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
3
poisonously adverb

Examples of poisonous in a Sentence

Chocolate is poisonous to dogs. This species of spider is extremely poisonous.
Recent Examples on the Web
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.
Nitrogen oxides are poisonous gases that help form lung-damaging soot particles, which can travel hundreds of miles. Sammy Roth, Los Angeles Times, 8 May 2025 After the poisonous snowfall begins, Salvo sets out to rescue his daughter, Clara, who was on a boat at the beginning of the attack. Caroline Blair, People.com, 6 May 2025 The tiny frog is known for the striking yellow and black markings that cover its body, which warn predators of its poisonous skin. Sara Hashemi, Smithsonian Magazine, 5 May 2025 In the first episode, the family's health mentor told them to stay away from it, saying the fruit is poisonous and could potentially kill anyone who ingests it. Randall Colburn, EW.com, 4 Apr. 2025 See All Example Sentences for poisonous

Word History

First Known Use

15th century, in the meaning defined at sense 2

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

Browse Nearby Words

Cite this Entry

“Poisonous.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/poisonous. Accessed 13 May. 2025.

Kids Definition

poisonous

adjective
poi·​son·​ous ˈpȯiz-nəs How to pronounce poisonous (audio)
-ᵊn-əs
: containing poison : having or causing an effect of poison
poisonously adverb

Medical Definition

poisonous

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

Last Updated: - Updated example sentences
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