poisonous
Americanadjective
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full of or containing poison.
poisonous air; a poisonous substance.
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harmful; destructive.
poisonous to animals; poisonous rumors.
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deeply malicious; malevolent.
poisonous efforts.
adjective
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having the effects or qualities of a poison
-
capable of killing or inflicting injury; venomous
-
corruptive or malicious
Other Word Forms
Etymology
Origin of poisonous
Compare meaning
How does poisonous compare to similar and commonly confused words? Explore the most common comparisons:
Explanation
What do arsenic, cyanide, and bleach all have in common? They're poisonous. In other words, if you ingest these poisonous chemicals, you will most likely die or become very ill. If something is poisonous, you'd better not eat, drink, inhale, or touch it: it will make you sick. Some poisonous materials can even kill you. Of course, this adjective is derived from the noun poison, which is a toxic substance. You can also calls things poisonous if they're harmful in less physical ways. Spreading lies about someone is poisonous. Betraying a friend is poisonous. What both kinds of poisonous things have in common is that they do damage.
Vocabulary lists containing poisonous
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Harmful, List 2
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-ious, -eous, -ous
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
He said variable annuities are stupid and poisonous, but he claimed that fixed-rate annuities are the sparkly, rainbow-fairyland of investments if you know the right ones.
From MarketWatch • Jun. 12, 2026
Three people were recently hospitalized after eating poisonous wild mushrooms foraged in California wine country amid an unprecedented outbreak of illness and deaths linked to the practice statewide, health officials in Napa County announced.
From Los Angeles Times • May 15, 2026
It’s got poisonous lead in it from paint.
From Salon • Mar. 6, 2026
But there are dozens of other poisonous snake species for which India does not have targeted antivenom.
From BBC • Feb. 1, 2026
They’d barely been able to stumble a hundred yards in this poisonous place without dying.
From "The House of Hades" by Rick Riordan
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
