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 This native plant is poisonous except for the ripe, yellow fruit (discard the seeds, a forager friend says) but people here make May apple jelly and wine. Daryln Brewer Hoffstot Kristian Thacker, New York Times, 23 Mar. 2024 However, the scientific community long ago debunked the myth that mold was poisonous to breathe. Kelly G. Richardson, Orange County Register, 22 Mar. 2024 For those planning mushroom hunting, review Michigan’s 50 poisonous mushroom species. Detroit Free Press, 14 Mar. 2024 These poisonous ideas are center stage in the drive to impeach Homeland Security Secretary Alejandro Mayorkas. TIME, 6 Feb. 2024 The root can be confused with the poisonous plant hemlock, which is fatal if ingested. Barbie Cervoni, Verywell Health, 11 Mar. 2024 Removing poisonous lead pipes so every child can drink clean water without risk of getting brain damage. USA TODAY, 8 Mar. 2024 The heat from this ignition starts the decomposition of the sodium azide, which is poisonous, and the generation of nitrogen gas to fill the air bag in seconds. Detroit Free Press, 25 Feb. 2024 All parts of the oleander (Nerium oleander), a beautiful flowering shrub native to the Mediterranean, are poisonous. Deb Wiley, Better Homes & Gardens, 19 Feb. 2024

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'poisonous.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

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

Dictionary Entries Near poisonous

Cite this Entry

“Poisonous.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/poisonous. Accessed 28 Mar. 2024.

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

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