tox·​ic·​i·​ty | \ täk-ˈsi-sə-tē How to pronounce toxicity (audio) \
plural toxicities

Definition of toxicity

: 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

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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 Animal studies done with an adenovirus vaccine against Ebola showed no maternal or fetal toxicity in female rabbits vaccinated during or immediately before pregnancy, according to Johnson & Johnson. Mariana Lenharo, Scientific American, "Why COVID Vaccines Are Likely Safe for Pregnant People," 2 Feb. 2021 Unfortunately, the spiritual toxicity unleashed by some in this congregation will likely outlast the pandemic. Amy Dickinson, oregonlive, "Ask Amy: 13-year-old’s racy Instagram alarms family friend," 4 Oct. 2020 Unfortunately, the spiritual toxicity unleashed by some in this congregation will probably outlast the pandemic. Washington Post, "Ask Amy: Racy Instagram postings alarm family friend," 4 Oct. 2020 Unfortunately, the spiritual toxicity unleashed by some in this congregation will likely outlast the pandemic. Amy Dickinson, Detroit Free Press, "Racy Instagram postings alarm family friend," 4 Oct. 2020 The 'Blue Monster' course at Miami's Doral Resort, which Trump bought in 2012, was home to a PGA Tour event for more than 50 years until the toxicity of his 2016 presidential campaign forced the Tour to relocate the tournament to Mexico City. Eamon Lynch, Detroit Free Press, "Donald Trump is a scar on the game of golf: Opinion," 10 Jan. 2021 The caffeine content in both products as well as in teabags can also cause caffeine toxicity. Iris Katz,, "Pet Wise: Keeping pets and guests safe during unusual holiday season," 19 Dec. 2020 Graham Johnson and Patrick Davies of the University of Nottingham's School of Medicine decided to analyze the therapeutic effects and toxicity of the marvelous medicine, using ToxBase, a national database of poisons in the UK. Jennifer Ouellette, Ars Technica, "Don’t try this at home: George’s Marvelous Medicine is quite toxic," 17 Dec. 2020 Spence died of methamphetamine toxicity and pneumonia, according to the medical examiner., "'A wake-up call': 500 homeless people died in metro Phoenix in first 9 months of 2020," 17 Dec. 2020

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'toxicity.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of toxicity

1879, in the meaning defined above

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Time Traveler for toxicity

Time Traveler

The first known use of toxicity was in 1879

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Statistics for toxicity

Last Updated

23 Feb 2021

Cite this Entry

“Toxicity.” Dictionary, Merriam-Webster, Accessed 3 Mar. 2021.

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More Definitions for toxicity



English Language Learners Definition of toxicity

technical : the state of being poisonous or the degree to which something (such as a drug) is poisonous


tox·​ic·​i·​ty | \ täk-ˈsis-ət-ē How to pronounce toxicity (audio) \
plural toxicities

Medical Definition of toxicity

: the quality, state, or relative degree of being toxic or poisonous

More from Merriam-Webster on toxicity

Nglish: Translation of toxicity for Spanish Speakers

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