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 Municipalities and counties may add additional noxious weeds to their lists. Jennifer Rude Klett, Milwaukee Journal Sentinel, 16 Sep. 2021 The other ordinance presented by Shachner prohibits certain types of bamboo, as well as updates the city’s noxious weed list. John Benson, cleveland, 22 Sep. 2021 But on a bad day, humanity’s noxious disregard for nature drives him into states of dark hopelessness — of solastalgia., 16 Sep. 2021 Wisconsin state law allows noxious plants to be regulated and enforced by local municipalities and counties. Jennifer Rude Klett, Milwaukee Journal Sentinel, 16 Sep. 2021 But in the two decades since then, the number of deaths among survivors and responders—who spent months inhaling the noxious dust, chemicals, fumes and fibers from the debris—has continued creeping up. Tara Haelle, Scientific American, 10 Sep. 2021 Other noxious invaders are poised to make the same trip., 30 Aug. 2021 No doubt that’s still a noxious motivator for at least a few people who want to limit access to the shore. James Rainey, Los Angeles Times, 27 Aug. 2021 This, combined with the ozone, made worse by the heat, and the pesticides from the nearby fields, led to a noxious, inflammatory cocktail that swirled deep in Nicolas’ family’s lungs. Elizabeth Weil, ProPublica, 22 Aug. 2021

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

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

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Dictionary Entries Near noxious

noxal surrender



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Last Updated

13 Oct 2021

Cite this Entry

“Noxious.” Dictionary, Merriam-Webster, Accessed 20 Oct. 2021.

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More Definitions for noxious



English Language Learners Definition of noxious

: harmful to living things : toxic


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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