nox·ious | \ ˈnäk-shəs \

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

Nuisance laws had targeted problems like noxious odors or chemical spills that crept across property lines. Emily Badger, New York Times, "How ‘Not in My Backyard’ Became ‘Not in My Neighborhood’," 3 Jan. 2018 Thousands of people are protesting the noxious fumes coming from overcrowded landfills surrounding Moscow, blaming them for causing illnesses. Washington Post, "A big stink erupts over landfills ringing Russia’s capital," 19 June 2018 The workers were accompanied by heavily armed soldiers wearing masks to avoid breathing in noxious fumes. Sonia Perez D.,, "Guatemala volcano death toll hits 62," 4 June 2018 Many weeds are irksome or obnoxious, but some are even noxious by law. Margaret Lauterbach, idahostatesman, "Know the proper ways to attack all of our plentiful weeds," 1 June 2018 The ash is a new irritant for a town that's used to coping with volcanic smog from noxious fumes seeping from the summit and eruption vents. Jennifer Sinco Kelleher,, "Final exams moved to gym as ash fills Hawaii classroom," 25 May 2018 And in the air, noxious fumes from the volcano are what some officials say could be the greatest threat to public health in the wake of its eruption. The Washington Post,, "'Fast-moving situation': Lava shoots through Hawaii neighborhood," 6 May 2018 Downwind from the nearby Yadrovo landfill site, the noxious blend of sulphur, rot and methane becomes unbearable. The Economist, "Protests outside Moscow about rubbish turn serious," 12 Apr. 2018 Matt Lake said about 100 fish died recently in an isolated incident in the 21-acre lake when the heat index rose to 110 degrees the day after the lake was treated for algae, duckweed and other noxious weeds. Karen Caffarini, Post-Tribune, "About 100 fish found dead in Bon Aire Lake: Merrillville official," 13 July 2018

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, from Latin, from noxa harm; akin to Latin nocēre to harm, nec-, nex violent death, Greek nekros dead body

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Dictionary Entries near noxious


noxal action

noxal surrender





Statistics for noxious

Last Updated

19 Sep 2018

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Time Traveler for noxious

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

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English Language Learners Definition of noxious

: harmful to living things


nox·ious | \ ˈnäk-shəs \

Kids Definition of noxious

: causing harm noxious fumes


nox·ious | \ ˈnäk-shəs \

Medical Definition of noxious 

: physically harmful or destructive to living beings noxious wastes

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More from Merriam-Webster on noxious

Thesaurus: All synonyms and antonyms for noxious

Spanish Central: Translation of noxious

Nglish: Translation of noxious for Spanish Speakers

Britannica English: Translation of noxious for Arabic Speakers

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the setting in which something occurs

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