nox·​ious | \ ˈnäk-shəs How to pronounce noxious (audio) \

Definition of noxious

1a : physically harmful or destructive to living beings noxious waste noxious fumes
b : constituting a harmful influence on mind or behavior especially : morally corrupting noxious doctrines
2 : disagreeable, obnoxious this noxious political scandal— H. L. Ickes

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Other Words from noxious

noxiously adverb
noxiousness noun

Choose the Right Synonym for noxious

pernicious, baneful, noxious, deleterious, detrimental mean exceedingly harmful. pernicious implies irreparable harm done through evil or insidious corrupting or undermining. the claim that pornography has a pernicious effect on society baneful implies injury through poisoning or destroying. the baneful notion that discipline destroys creativity noxious applies to what is both offensive and injurious to the health of a body or mind. noxious chemical fumes deleterious applies to what has an often unsuspected harmful effect. a diet found to have deleterious effects detrimental implies obvious harmfulness to something specified. the detrimental effects of excessive drinking

Examples of noxious in a Sentence

mixing bleach and ammonia can cause noxious fumes that can seriously harm you noxious smog that for years has been encrusting the historic cathedral with soot
Recent Examples on the Web The companies also face scrutiny about how hate speech and other noxious online material can spill into the offline world, leading to calls to better control content. New York Times, "A Global Tipping Point for Reining In Tech Has Arrived," 20 Apr. 2021 The roof and guttering will be repaired to stop any more water getting in, the windows and doors will be boarded up and any internal pipes that once held noxious chemicals will be drained. Jo Caird, Smithsonian Magazine, "This London Building Tells the Story of a Century’s Worth of Disease and Epidemics," 5 Apr. 2021 Romero and her coworkers were overcome by the noxious fumes, suffering severe burning in their eyes, coughing, lesions and trouble breathing. USA Today, "Rationing insulin. Skipping meals. One woman’s struggle to survive on minimum wage," 6 Apr. 2021 According to The Transmutational Garden, most people consider a dandelion to be a weed, however, it is not listed on the U.S. Department of Agriculture's list of noxious weeds. Mckenzie Sadeghi, USA TODAY, "Fact check: Viral meme on benefits of dandelions is partly false," 30 Mar. 2021 Demonstrators used noxious spray to get through the police line and enter into a building vestibule. oregonlive, "Video shot from multiple angles reveals more of how Rep. Mike Nearman enabled demonstrators to illegally enter the Oregon Capitol and what happened next," 11 Jan. 2021 Civilians working at the refineries, who are often children, are exposed to noxious fumes from manually heating crude and spills, leaking pipes and explosions are common. Joseph Hincks, Time, "How Syria's Decade-Long War Has Left a Toxic Environmental Legacy," 15 Mar. 2021 In 2013, people living near the Westmoreland landfill began complaining of noxious fumes that were causing them nausea, headaches, and trouble breathing. Eliza Griswold, The New Yorker, "When the Kids Started Getting Sick," 2 Mar. 2021 Researchers have finished an early feasibility study of how the noxious chemical might be concentrated and used as propulsion fuel. Caroline Delbert, Popular Mechanics, "Ammonia Can Officially Work As Jet Fuel," 31 Aug. 2020

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'noxious.' 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 noxious

15th century, in the meaning defined at sense 1a

History and Etymology for noxious

Middle English noxius, borrowed from Latin noxius "guilty, delinquent, harmful, injurious" (derivative of noxa "injurious behavior, harm, mischief") + -us -ous; noxa derivative (perhaps with -s- as a desiderative suffix) from the base of nocēre "to damage (things), injure, harm (persons)," going back to Indo-European *noḱ-éi̯e- "destroy" (with semantic weakening in Latin), whence also Sanskrit nāśáyati "(s/he) destroys," causative derivatives from a verbal base *neḱ- "disappear, pass out of existence, perish," whence, with varying ablaut grades, Sanskrit náśyati "(s/he) is lost, perishes," Avestan nąsat̰ "has gone away, is lost," Tocharian B näk- "destroy," (in middle voice) "disappear, be destroyed"

Note: The Indo-European verbal base *neḱ- is also the source of a root noun attested as Latin nec-, nex "violent death, killing"; see necro-.

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Time Traveler for noxious

Time Traveler

The first known use of noxious was in the 15th century

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Statistics for noxious

Last Updated

28 Apr 2021

Cite this Entry

“Noxious.” Dictionary, Merriam-Webster, Accessed 9 May. 2021.

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More Definitions for noxious



English Language Learners Definition of noxious

formal : harmful to living things


nox·​ious | \ ˈnäk-shəs How to pronounce noxious (audio) \

Kids Definition of noxious

: causing harm noxious fumes


nox·​ious | \ ˈnäk-shəs How to pronounce noxious (audio) \

Medical Definition of noxious

: physically harmful or destructive to living beings noxious wastes

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