noxious

adjective

nox·​ious ˈnäk-shəs How to pronounce noxious (audio)
1
a
: 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 scandalH. L. Ickes
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 Smoke from the fires, particularly blazes that burned in Quebec, wafted as far south as Florida and blanketed several cities in the United States and southern Canada in a noxious cloud. Ian Austen, New York Times, 4 Mar. 2024 This fascinating behavior, where the stomach is inverted, is believed to serve as a mechanism for expelling noxious or indigestible items from the gastrointestinal tract. Melissa Cristina Márquez, Forbes, 2 Mar. 2024 Some even consume noxious fare that few other species would dare eat. Jack Tamisiea, Scientific American, 23 Feb. 2024 Councilors in the mayor’s office moved quickly to assure residents that the latest noxious smell was not emanating from raw sewage, as happened just weeks before when a water pump collapsed in a northeastern suburb. Lynsey Chutel, New York Times, 20 Feb. 2024 Measles is again on the march across the world, thanks to anti-vaxxers such as RFK Jr. Dec. 19, 2023 That brings us to the noxious posts by Simberg and Steyn. Michael Hiltzik, Los Angeles Times, 13 Feb. 2024 With some additional research and adjustments, aluminum’s longtime, notoriously noxious waste could finally become something useful—and far more eco-friendly. Andrew Paul, Popular Science, 7 Feb. 2024 But the quantity of steam being ejected was too prodigious to be dispersed; the noxious taste of it invaded our space. Richard Brookhiser, National Review, 25 Jan. 2024 Mammoth Terraces, part of the iconic federal park, are known for their visually striking rock formations and terraces, as well as containing pools and springs that happen to be filled with extremely hot, noxious water. Martha Ross, The Mercury News, 20 Jan. 2024

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'noxious.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

Etymology

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-.

First Known Use

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

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

Dictionary Entries Near noxious

Cite this Entry

“Noxious.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/noxious. Accessed 19 Mar. 2024.

Kids Definition

noxious

adjective
nox·​ious ˈnäk-shəs How to pronounce noxious (audio)
: harmful especially to health : unwholesome
noxious fumes

Medical Definition

noxious

adjective
nox·​ious ˈnäk-shəs How to pronounce noxious (audio)
: physically harmful or destructive to living beings
noxious wastes

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