noxious

adjective

nox·​ious ˈnäk-shəs 

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

Synonyms

• insalubrious
• noisome
• sickly
• unhealthful
• unhealthy
• unwholesome

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 wildfires in California and other places, including Canada, has blown far beyond the confines of the flames, with noxious particles reaching as far as the East Coast of the U.S. and Europe. —Tribune News Service, Hartford Courant, 18 June 2024

Yet the election results have meaning, and they have been cast, rather too narrowly but understandably, as another victory for the extreme right—a victory particularly noxious in France and Germany, where more or less openly neo-fascist parties won startlingly large shares of the vote. —Adam Gopnik, The New Yorker, 16 June 2024

Animals that chew their cud can emit noxious gases with an astounding impact on the environment. —Sandee Lamotte, CNN, 10 June 2024

Warming fresh and sea waters more frequently become home to noxious blooms of toxic algae and bacteria. —Vox Staff, Vox, 3 June 2024

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

Kids Definition

noxious

adjective

nox·​ious ˈnäk-shəs 

: harmful especially to health : unwholesome

noxious fumes

Medical Definition

noxious

adjective

nox·​ious ˈnäk-shəs 

: physically harmful or destructive to living beings

noxious wastes