noxious

adjective nox·ious \ ˈnäk-shəs \

Definition of noxious

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 scandal
—H. L. Ickes

—

noxiously

adverb

—

noxiousness

noun

See noxious defined for English-language learners

See noxious defined for kids

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 of noxious from the Web

Many more photos of the incident were seen via social media, as thick clouds of noxious smoke were pictured above the famous European ground, which understandably caused many to worry.

— SI.com, "Thick Smoke Seen Over Bayern's Allianz Arena Sparks Temporary Fears in Munich," 29 Aug. 2017
The American Museum of Natural History covers the noxious range in the Power of Poison, a new exhibit that runs Oct. 21 to Feb. 11.

— liz biro, Indianapolis Star, "10 new things Indy arts and pop culture geeks should check out this fall," 28 Aug. 2017
But the study showed that even a few trolls can swing a place into a noxious realm.

— max londberg, kansascity, "Here’s where the nastiest online trolls live — feel free to comment," 25 Aug. 2017
But recently the Whitneys, like some of their neighbors, reported noxious odors seeping from the windows.

— mary wisniewski, chicagotribune.com, "Midway residents want city to replace foul-smelling, noise-reducing windows," 24 Aug. 2017
This most noxious of all weeds in Texas requires special treatments.

— neil sperry, star-telegram, "Brave the heat for these critical gardening tasks for the second half of August," 8 Aug. 2017
Perhaps this is why the patriotic impulses behind Dunkirk, generally so noxious to the trans-Atlantic liberal elite, have gone so widely unremarked, a bad review or two at The New Republic notwithstanding.

— max bloom, National Review, "Dunkirk and Our Crisis of National Identity," 1 Aug. 2017
Bindweed (Convolvulus arvensi) is a noxious weed that resembles morning glory.

— ellen nibali, baltimoresun.com, "Garden Q&A: Tree damaged by lightning," 18 July 2017
The noxious gases that flame retardants emit during fires can be deadly in their own right.

— anne kniggendorf, kansascity, "Today’s homes burn faster than ones in the past, and your furniture may be to blame," 14 July 2017

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.

Origin and Etymology of noxious

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

NEW! Time Traveler

First Known Use: 15th century

See Words from the same year

noxious Synonyms

Synonyms

insalubrious, noisome, unhealthy, sickly, unhealthful, unwholesome

Antonyms

healthful, healthy

Related Words

germy, insanitary, unhygienic, unsanitary; nonnutritious; poisonous, toxic; fatal, lethal, mortal

Near Antonyms

hygienic, sanitary; nutritious

Synonym Discussion of noxious

pernicious, baneful, noxious, deleterious, detrimental mean exceedingly harmful. pernicious implies irreparable harm done through evil or insidious corrupting or undermining.