toxicity

noun

tox·​ic·​i·​ty täk-ˈsi-sə-tē How to pronounce toxicity (audio)
plural toxicities
: the quality or state of being toxic: such as
a
: the quality, state, or relative degree of being poisonous
measuring the toxicity level of the soil
The toxicity of some chemical agents degrades significantly over time, so it is unclear how lethal the stockpiles are.David S. Cloud
Administering a cocktail of drugs would dilute the toxicities of the different drugs and minimize the development of viral resistance to them.Rudy M. Baum and Ron Dagani
b
: an extremely harsh, malicious, or harmful quality
In the past few days, I've tuned in to C-SPAN to watch a number of the televised Senate debates, which illustrate all too vividly the toxicity of an uncivil tongue.Connie Schultz
In much of the ensuing commentary, court watchers worried that the justices' soaring rates of written dissents, nasty and personal attacks and scathing remarks read aloud from the bench bespeak a new toxicity in Supreme Court discourse.Dahlia Lithwick

Did you know?

Toxicity is often a relative thing; in the words of a famous old saying, "The dose makes the poison". Thus, it's possible to die from drinking too much water, and lives have been saved by tiny doses of arsenic. Even though botulinum toxin is the most toxic substance known, it's the basic ingredient in Botox, which is injected into the face to get rid of wrinkles. With some poisons, mere skin contact can be lethal; others are lethal when breathed into the lungs in microscopic amounts. To determine if a chemical will be officially called a poison, researchers often use the "LD50" test: If 50 milligrams of the substance for every kilogram of an animal's body weight results in the death of 50% of test animals, the chemical is a poison. But there are problems with such tests, and toxicity remains a very individual concept.

Examples of toxicity in a Sentence

Recent Examples on the Web
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Despite being used in vaccines since the 1930s, there has been ongoing concern about the potential toxicity of aluminum, especially over the long term. New Atlas, 15 July 2025 Pratt quickly became known for transforming toxicity into high ratings, but at the expense of his own mental health. Rachel Flynn, People.com, 15 July 2025 This raises the possibility of cardiotoxic effects, like low blood pressure and cardiovascular collapse, as well as neurological toxicity, such as muscle weakness or dysfunction of the autonomic nervous system, which controls things like heart rate and breathing. ArsTechnica, 10 July 2025 In December 2023, Navarro and Griffin also clashed on air over a Hot Topics segment about toxicity in the workplace. EW.com, 9 July 2025 See All Example Sentences for toxicity

Word History

First Known Use

1873, in the meaning defined above

Time Traveler
The first known use of toxicity was in 1873

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Cite this Entry

“Toxicity.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/toxicity. Accessed 22 Jul. 2025.

Medical Definition

toxicity

noun
tox·​ic·​i·​ty täk-ˈsis-ət-ē How to pronounce toxicity (audio)
plural toxicities
: the quality, state, or relative degree of being toxic or poisonous

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