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

Employing a blend of industrial fermentation and sustainable chemistry, Pili’s production method slashes the use of noxious chemicals and fossil fuels, a significant concern for many brands. —Angela Lei, Forbes, 6 Jan. 2025

This wildly unsteady The-Fountainhead-meets-There-Will-Be-Blood plotting follows the most noxious strain in contemporary cinema. —Armond White, National Review, 3 Jan. 2025

Rogan developed a following first and foremost as a comedian, a mixed-martial-arts personality, and a dude who’s really into galaxy-brain ideas, weird conspiracy theories, and his own beliefs about the world, some of which are noxious. —Nicholas Quah, Vulture, 11 Nov. 2024

Two groups of residents have already filed suit against L.A.’s sanitation department over air quality issues immediately after the spill, one specifically alleging the city’s failure to monitor noxious gases. —Grace Toohey, Los Angeles Times, 16 Dec. 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