1
: containing or being poisonous material especially when capable of causing death or serious debilitation
toxic waste
a toxic radioactive gas
an insecticide highly toxic to birds
2
: exhibiting symptoms of infection or toxicosis
the patient became toxic two days later
3
: extremely harsh, malicious, or harmful
toxic sarcasm
4
: relating to or being an asset that has lost so much value that it cannot be sold on the market
: a toxic substance
—usually used in plural
Synonyms
Examples of toxic in a Sentence
Adjective
The fumes from that chemical are highly toxic.
Tests will be run to determine if the landfill is toxic.
Noun
tested for toxics in the water supply
Recent Examples on the Web
Jonathan Bing, Deadline, 22 Nov. 2024
However, methanol becomes formaldehyde—a cancer-causing chemical used in industrial glues and embalming corpses—and formate, or formic acid, which is a strong and toxic acid.
—Matt Robison, Newsweek, 21 Nov. 2024
Scott Travers, Forbes, 22 Nov. 2024
According to Apolo, theobromine, an alkaloid in the cacao beans used to make chocolate, makes chocolate toxic to canines.
—Kelli Bender, People.com, 29 Oct. 2024
See all Example Sentences for toxic 
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Adjective
The heavy ad load had a toxic effect on the TV ecosystem.
—Jonathan Bing, Deadline, 22 Nov. 2024
However, methanol becomes formaldehyde—a cancer-causing chemical used in industrial glues and embalming corpses—and formate, or formic acid, which is a strong and toxic acid.
—Matt Robison, Newsweek, 21 Nov. 2024
Noun
Fipronil is also high toxic to fish and aquatic invertebrates.
—Scott Travers, Forbes, 22 Nov. 2024
According to Apolo, theobromine, an alkaloid in the cacao beans used to make chocolate, makes chocolate toxic to canines.
—Kelli Bender, People.com, 29 Oct. 2024
See all Example Sentences for toxic
Dictionary Entries Near toxic
Cite this Entry
“Toxic.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/toxic. Accessed 1 Dec. 2024.
Copy CitationMedical Definition
toxic
1 of 2 adjective
tox·ic
ˈtäk-sik 
1
: containing or being poisonous material especially when capable of causing serious injury or death
toxic drugs
toxic gas
2
: of, relating to, or caused by a poison or toxin
toxic liver damage
3
a
: affected by a poison or toxin
b
: affected with toxemia of pregnancy
toxic pregnant women
toxic
2 of 2 noun
: a toxic substance
Legal Definition
toxic
adjective
tox·ic
ˈtäk-sik
1
: containing or being poisonous material especially when capable of causing death or serious debilitation
2
: having substantially lowered worth
specifically
: relating to or being an asset that has lost so much value that it cannot be sold on the market
toxic assets
toxic subprime loans
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