noxious
Americanadjective
-
harmful or injurious to health or physical well-being.
noxious fumes.
- Synonyms:
- deleterious, detrimental, nocuous, unhealthy, unwholesome, hurtful
- Antonyms:
- harmless
-
morally harmful; corrupting; pernicious.
a noxious plan to spread dissension.
- Synonyms:
- corruptive
- Antonyms:
- harmless
adjective
-
poisonous or harmful
-
harmful to the mind or morals; corrupting
Other Word Forms
Derived Forms
Etymology
Origin of noxious
1605–15; < Latin noxius harmful, hurtful, injurious, equivalent to nox ( a ) harm, hurt, injury (akin to nocēre to do harm, inflict injury; see innocent) + -ius -ious
Explanation
Something noxious is harmful and could be even fatal — whether it is colorless, odorless, and invisible like carbon monoxide, or dark, strong-smelling, and obvious, like black smoke from a fire. People are called noxious too when they hurt others with cruelty or mental anguish. English and Latin roots for noxious are related to the meanings of "harm," "damage," and "injury." While obnoxious might come to mind when seeing the word noxious, obnoxious is a much less damaging adjective to describe someone annoying. Most uses for noxious involve real physical or emotional damage unless the word is used in exaggeration. Examples range from "the noxious gas fumes made the dog pass out" to "his cologne was so noxious I had to exit the elevator and take the stairs."
Vocabulary lists containing noxious
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Like Kennedy, he failed to end a noxious regime, but he still has cards if he’s willing to play them.
From The Wall Street Journal • May 1, 2026
"So, they can cope with higher levels of noxious irritants produced by cold exposure."
From Science Daily • Mar. 26, 2026
Toilets crawling with rats, maggots and flies became so noxious that neighbors began defecating on the surrounding dirt roads.
From Salon • Dec. 16, 2025
It's hard enough to stop things getting noxious even when two title rivals are in different teams, such as in the tense relationship between Hamilton and Max Verstappen in 2021.
From BBC • Nov. 26, 2025
Light from these ornate lanterns gave the room a hazy yellow glow, and thick, noxious incense filled my nose and stung my eyes.
From "The Detective's Assistant" by Kate Hannigan
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
