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 One of the most noxious of former President Joe Biden’s leftover regulatory rules applies to partnerships — an increasingly common form of business organization and expansion. Stephen Moore, Boston Herald, 13 Sep. 2025 Along with the swamp eels, scientists in the USGS Wetland and Aquatic Research Center have been most concerned about the spread of Cuban tree frogs, which secrete noxious chemicals that are harmful to humans, and alligatorweed, which clogs waterways that can impact infrastructure. Wesley Bruer, CNN Money, 8 Sep. 2025 With the original Toxic Avenger creator’s blessing, Macon Blair has brought the cult franchise back from its noxious cinematic dumping grounds. Glenn Garner, Deadline, 7 Sep. 2025 These critics object that honoring Confederates is really celebrating noxious symbols of slavery and white supremacy. Time, 5 Sep. 2025 See All Example Sentences for noxious
Recent Examples of Synonyms for noxious
Adjective
  • But to isolate gold, galamsey workers typically use poisonous mercury, which pollutes drinking water and farmland and has been linked to serious illness and birth defects.
    Charlie Campbell, Time, 15 Oct. 2025
  • However, new evidence indicates that exposure to the poisonous element is not necessarily a new issue.
    Andrew Paul, Popular Science, 15 Oct. 2025
Adjective
  • The findings come just a couple years after another study conducted by Spanish and Brazilian researchers revealed the existence of potentially harmful bisphenol chemicals in clothing sold in Spain for pregnant women, newborns and toddlers.
    Jennifer Bringle, Sourcing Journal, 22 Oct. 2025
  • According to one study, people may become either psychologically or physically dependent on caffeine, which may be harmful.
    Brittany Lubeck, Verywell Health, 22 Oct. 2025
Adjective
  • Football is a way of bringing people together irrespective of their faith, colour or religion and this disgusting decision does the exact opposite.
    Jackson Thompson, FOXNews.com, 18 Oct. 2025
  • These are more disgusting smears peddled by the media and billboard law firms.
    Billal Rahman, MSNBC Newsweek, 16 Oct. 2025
Adjective
  • Unknown dangers Many personal care products — from lipstick to shampoo and moisturizer — still contain potentially toxic chemicals.
    Kimberly Richardson, CNN Money, 21 Oct. 2025
  • The test can detect trace amounts of minerals and toxic metals in their system, providing information at levels even smaller than a traditional blood test can find.
    Christine Persaud, USA Today, 20 Oct. 2025
Adjective
  • This means too much potassium in your blood, which can be dangerous if not treated.
    Merve Ceylan, Health, 20 Oct. 2025
  • The Mark is a spy flick centered on Eden (Alba), an enigmatic spy on a covert and dangerous mission.
    Matt Grobar, Deadline, 20 Oct. 2025
Adjective
  • The Broncos escaped, but this was ugly.
    Luca Evans, Denver Post, 20 Oct. 2025
  • On the other side, there was just as much commotion, but these conversations were almost hysterical — and far uglier.
    Julyssa Lopez, Rolling Stone, 19 Oct. 2025
Adjective
  • The change comes amid concerns about fireworks causing unhealthful air.
    Rong-Gong Lin II, Los Angeles Times, 19 June 2025
  • Health professionals encourage people to use lean cuts of meat because most of the fat in animal products is unhealthful saturated fat, which can raise the risk of heart disease and cancer.
    Bethany Thayer, Detroit Free Press, 22 June 2024
Adjective
  • Kalshi’s proclamations about geolocation expenses having a serious adverse effect on its budget are disputed by people and companies from the gambling establishment.
    Dan Bernstein, Sportico.com, 16 Oct. 2025
  • For the descendants of fired, demoted, and aspiring civil servants, the adverse economic effects persisted for generations.
    Time, Time, 14 Oct. 2025

Browse Nearby Words

Cite this Entry

“Noxious.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/noxious. Accessed 24 Oct. 2025.

More from Merriam-Webster on noxious

Last Updated: - Updated example sentences
Love words? Need even more definitions?

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