Definition of noxiousnext
1
as in poisonous
bad for the well-being of the body mixing bleach and ammonia can cause noxious fumes that can seriously harm you

Synonyms & Similar Words

Relevance

Antonyms & Near Antonyms

2
3

Synonym Chooser

How is the word noxious different from other adjectives like it?

Some common synonyms of noxious are baneful, deleterious, detrimental, and pernicious. While all these words mean "exceedingly harmful," noxious applies to what is both offensive and injurious to the health of a body or mind.

noxious chemical fumes

When is it sensible to use baneful instead of noxious?

The words baneful and noxious can be used in similar contexts, but baneful implies injury through poisoning or destroying.

the baneful notion that discipline destroys creativity

When would deleterious be a good substitute for noxious?

In some situations, the words deleterious and noxious are roughly equivalent. However, deleterious applies to what has an often unsuspected harmful effect.

a diet found to have deleterious effects

When could detrimental be used to replace noxious?

While the synonyms detrimental and noxious are close in meaning, detrimental implies obvious harmfulness to something specified.

the detrimental effects of excessive drinking

When might pernicious be a better fit than noxious?

The meanings of pernicious and noxious largely overlap; however, pernicious implies irreparable harm done through evil or insidious corrupting or undermining.

the claim that pornography has a pernicious effect on society

Example Sentences

Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Recent Examples of noxious Dry fields are also vulnerable to noxious weeds like leafy spurge and toadflax, which are toxic to cattle and unpalatable to native ungulates like deer and pronghorn antelope. Krista Kafer, Denver Post, 7 Apr. 2026 Bully feels custom-designed to please the diehards exhausted by his noxious antics. Kieran Press-Reynolds, Pitchfork, 1 Apr. 2026 Over time, however, the culture on the ground became just as noxious as Ye’s most unhinged instincts. Jeff Ihaza, Rolling Stone, 31 Mar. 2026 Helpful sources at your university agricultural extension program can usually confirm the identity of noxious weeds like giant hogweed and poison hemlock. Natalie Krebs, Outdoor Life, 26 Mar. 2026 See All Example Sentences for noxious
Recent Examples of Synonyms for noxious
Adjective
  • Hydrangeas are poisonous to dogs and cats.
    Sophia Beams, Better Homes & Gardens, 2 May 2026
  • Restoring the balance of the humors through profusely bleeding the patient or inducing vomiting or diarrhea with the poisonous plant hellebore.
    Literary Hub, Literary Hub, 28 Apr. 2026
Adjective
  • South Florida frequently sees sargassum washing ashore on its beaches, but the brown seaweed generally isn't harmful to humans.
    Sarah Perkel, USA Today, 4 May 2026
  • Companies should be required to disclose how their algorithms promote content to minors and be held responsible for knowingly amplifying harmful material, including content linked to self-harm, exploitation, or harassment.
    Linh Tat, Oc Register, 4 May 2026
Adjective
  • What a disgusting story all around.
    Zach Dean OutKick, FOXNews.com, 29 Apr. 2026
  • Making a disgusting joke about assassinating the President #2.
    Ted Johnson, Deadline, 28 Apr. 2026
Adjective
  • The mayor’s veto eliminated a measure to reduce public hostility at a time of toxic divisions fraying the city.
    Andrew Cuomo, New York Daily News, 2 May 2026
  • Harsh chemicals are prone to damaging grout over time, which can lead to issues like grout becoming porous and then collecting toxic fumes from cleaners that are then released back into the air.
    Ashlyn Needham, Southern Living, 2 May 2026
Adjective
  • Gabriel Basso stars as Sutherland, a formerly low-level FBI agent who has taken on increasingly dangerous assignments as part of a counterintelligence group within the bureau called Night Action.
    Rick Porter, HollywoodReporter, 4 May 2026
  • Bessent has compared the Fed's growing balance sheet to a dangerous lab experiment.
    Steve Liesman,Matt Peterson, CNBC, 4 May 2026
Adjective
  • The most expensive Republican primary for governor in Georgia history is still a dead heat despite a staggering avalanche of ad spending and one of the ugliest intraparty fights in recent memory.
    Greg Bluestein, AJC.com, 30 Apr. 2026
  • Ohm, well played by Scott who can wither with you with a look, is the classic ugly American and is rude to everyone at the hotel, but those putdowns and cruelty hides his self loathing.
    Randy Myers, Mercury News, 30 Apr. 2026
Adjective
  • The soil may contain pathogens, pesticides and other unhealthful things.
    Joan Morris, Mercury News, 9 Feb. 2026
  • The change comes amid concerns about fireworks causing unhealthful air.
    Rong-Gong Lin II, Los Angeles Times, 19 June 2025
Adjective
  • The most common adverse effects were jaundice, abdominal pain, and nausea.
    Patricia Weiser, Verywell Health, 1 May 2026
  • As of April 30, no adverse reactions due to the consumption of the breakfast pizzas had been reported.
    Greta Cross, USA Today, 1 May 2026

Browse Nearby Words

Cite this Entry

“Noxious.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/noxious. Accessed 9 May. 2026.

More from Merriam-Webster on noxious

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

More from Merriam-Webster