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
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capable of killing or inflicting injury; venomous
-
corruptive or malicious
Other Word Forms
Derived 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.
“Recent rains have contributed to the resurgence of poisonous wild mushrooms in California, including in Napa,” said a statement from Dr. Christine Wu, Napa County’s public health officer.
From Los Angeles Times • May 15, 2026
"The idea is to divide Russia from the outside world," says columnist Andrei Kolesnikov, from opposition outlet Novaya Gazeta, because of the belief that "this world is poisonous to the brains of Russians".
From BBC • Apr. 24, 2026
In this poisonous time, those who grin at the notion of playing a Traitor may think twice about the potential cost to their principles.
From Salon • Jan. 28, 2026
But time and again the poisonous isolation that absolute power imposes on its wielders blunted the edge of their insight and degraded the capacity of their societies.
From The Wall Street Journal • Jan. 26, 2026
By the end of the war, scientists in Europe uncovered evidence that it was germs, not poisonous miasma, that attacked the body.
From "Ambushed!" by Gail Jarrow
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.
