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

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 All of this is necessary, of course, to rectify a person's current diet and lifestyle choices, which are most certainly noxious and deplorable. Beth Mole, Ars Technica, 24 Mar. 2022 The Bonhomme Richard burned more than four days blanketing the neighborhoods nearest the base in noxious black smoke. Andrew Dyer, San Diego Union-Tribune, 10 Mar. 2022 On a summer day in Minnesota, because the air was noxious to breathe. Sarah Barker, Outside Online, 23 Aug. 2021 Neighbors complained for several years that the site emitted noxious fumes that gave them nosebleeds, headaches and respiratory problems like asthma. Nathan Solis, Los Angeles Times, 29 Mar. 2022 The noxious fumes that get trapped in our homes are also harmful, especially for children. New York Times, 11 Mar. 2022 The program promotes the planting of native species, the removal of noxious weeds, and the elimination of pesticides. Britany Robinson, Outside Online, 29 Oct. 2021 Even during talks with some truly noxious rivals throughout history, Washington would adopt a Russian proverb doveryai, no proveryai—or as Americans came to know it via Ronald Reagan, trust but verify. Philip Elliott, Time, 30 Mar. 2022 Exposures to the lung from other noxious substances besides tobacco smoke are occasionally the cause of COPD in nonsmokers. Dr. Keith Roach, oregonlive, 29 Mar. 2022 See More

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.

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

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noxal surrender



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Last Updated

10 May 2022

Cite this Entry

“Noxious.” Dictionary, Merriam-Webster, Accessed 17 May. 2022.

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More Definitions for noxious


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

More from Merriam-Webster on noxious

Nglish: Translation of noxious for Spanish Speakers

Britannica English: Translation of noxious for Arabic Speakers


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