poisonous

adjective

poi·​son·​ous ˈpȯiz-nəs 

ˈpȯi-zᵊn-əs

1

: destructive, harmful

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

: spiteful, malicious

poisonously adverb

Synonyms

• envenomed
• poison
• poisoned
• toxic
• venomous

Examples of poisonous in a Sentence

Chocolate is poisonous to dogs.

This species of spider is extremely poisonous.

Recent Examples on the Web

Smelly mushrooms are often called stinkhorns; they should be considered poisonous. 42. —Tom MacCubbin, Orlando Sentinel, 27 July 2024

And a very long list of organizations have Phase 2 trials ongoing for psychedelics ranging from LSD to 5-MeO-DMT (found in the poisonous secretions of a Sonoran Desert toad). —Oshan Jarow, Vox, 9 Aug. 2024

But in recent years, the poisonous practice has taken on new life, with people being doxed and extorted for cryptocurrency and, in the most extreme cases, potentially facing physical violence. —Matt Burgess, WIRED, 7 Aug. 2024

As the government eliminated private property and food became scarce, rice gruel became a staple and people began eating insects, bats, and even poisonous fruits. —Shamilee Vellu, Travel + Leisure, 2 Aug. 2024

Word History

First Known Use

15th century, in the meaning defined at sense 2

Kids Definition

poisonous

adjective

poi·​son·​ous ˈpȯiz-nəs 

-ᵊn-əs

: containing poison : having or causing an effect of poison

poisonously adverb

Medical Definition

poisonous

adjective

poi·​son·​ous ˈpȯiz-nəs, -ᵊn-əs 

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