Harmful, poisonous, or destructive, either physically through substances such as fumes and chemicals or figuratively through damaging ideas and influences.
The noxious gas forced workers to leave the building.
The novel exposes noxious attitudes toward women.
Farmers must control noxious weeds that threaten crops.
The article criticized the noxious influence of extremist groups.
The campaign challenged noxious myths about immigrants.
Similar words
harmful
pernicious
injurious
dangerous
deleterious
toxic
poisonous
hazardous
corrupting
toxic
Meanings
Physically harmful or poisonous
adjective
health
neutral
Harmful to living things or health, especially because it is poisonous, toxic, irritating, or destructive.
Usage
Use noxious for gases, fumes, chemicals, weeds, waste, or other things that can cause real harm.
Examples
The noxious gas forced workers to leave the building.
Children were warned not to touch the noxious chemicals.
Farmers must control noxious weeds that threaten crops.
The factory released noxious fumes into the air.
Authorities labeled the waste noxious and required special handling.
Masks protected the crew from noxious vapors.
Common mistakes
The word is often used for something merely unpleasant, but noxious normally implies actual harm or danger.
Incorrect
Correct
The perfume was noxious because I disliked it.
The perfume was unpleasant because I disliked it.
The music was noxious to my ears.
The music was painfully loud.
The noxious of the fumes worried inspectors.
The noxiousness of the fumes worried inspectors.
Similar words
harmful
poisonous
toxic
hazardous
injurious
dangerous
Harmful in influence or effect
adjective
social
formal
Damaging to people, values, or society by spreading harmful attitudes, ideas, or behavior.
Usage
Use noxious for ideas, rhetoric, stereotypes, or influences that are harmful rather than just annoying.
Examples
The politician's noxious rhetoric inflamed the crowd.
The article criticized the noxious influence of extremist groups.
Online forums can spread noxious ideas quickly.
The novel exposes noxious attitudes toward women.
Parents objected to the noxious stereotypes in the program.
The campaign challenged noxious myths about immigrants.
Common mistakes
The word is often confused with obnoxious, which means annoying or offensive rather than harmful.
Incorrect
Correct
He was noxious at dinner and interrupted everyone.
He was obnoxious at dinner and interrupted everyone.
The joke was noxious because it was loud.
The joke was obnoxious because it was loud.
The policy is obnoxious because it harms vulnerable families.
The policy is noxious because it harms vulnerable families.
Similar words
harmful
pernicious
deleterious
corrupting
toxic
malignant
Usage
Use noxious when the focus is real harm, danger, or corrupting influence, not simple annoyance or dislike.
Common mistakes
Noxious person is usually wrong when the meaning is merely annoying. Use obnoxious person instead.
Etymology
From Latin noxius, meaning “harmful” or “injurious,” from noxa, meaning “harm.”
FAQ
What does noxious mean?
Noxious means harmful, poisonous, or destructive to health, living things, or sometimes society and values.
Is noxious the same as obnoxious?
No. Noxious means harmful or poisonous, while obnoxious means annoying, offensive, or unpleasant.
Can a smell be noxious?
Yes, if the smell comes from something harmful or irritating, such as toxic fumes or dangerous waste.
What are noxious weeds?
Noxious weeds are harmful weeds that can damage crops, ecosystems, public health, or property.
Can noxious describe ideas?
Yes. Noxious can describe ideas or rhetoric that have a harmful or corrupting influence.
How do you pronounce noxious?
Noxious is pronounced /ˈnɑːkʃəs/.
Where does noxious come from?
Noxious comes from Latin noxius, meaning “harmful” or “injurious.”
What is a synonym for noxious?
Depending on the context, synonyms include harmful, poisonous, toxic, hazardous, and pernicious.
Comments & contributions
Know this word from another angle? Add a correction, a nuance, or a usage note. New posts go public after a quick review.
Newest
Top
Active
Contribution
Hardy Trout
4 days ago
dont reach for innoxious in normal writing. Say innocuous.
2
Reply
Contribution
Scarlet Bunting
5 days ago
I see learners pick noxious for every bad smell, especially in vocab tests. Sometimes the question only wants fetid or noisome. Noxious works better when the smell is from something harmful, poisonous, irritating, not just gross.
2
Reply
Bronze Panther
5 days ago
I lost a GRE question like this, picked noxious for smell and the answer wanted fetid
1
Contribution
Clever Stork
Jul 4
Med papers say noxious stimulus, meaning heat, pressure, etc that can damage tissue or set off pain pathways.
4
Reply
Ivory Hippo
Jul 9
this is why you see nociceptor beside it too. not a word most people need at dinner lol
0
Contribution
Warm Capybara
Jun 23
In plant stuff, noxious weed is often a legal label, not just a dramatic way to say ugly weed. The awkward bit is that the lists are local. A plant can be banned or regulated in one state, ignored in the next one, and sold in a nursery somewhere else because nobody has listed it there. So when two gardeners disagree about whether a plant is noxious, check the place they mean before correcting them.
8
Reply
Sincere Kudu
Jun 26
yep, where I live landlords get notices for certain weeds. Its not just garden-club language