toxic

American  

[tok-sik] / ˈtɒk sɪk /

adjective

1. of, pertaining to, affected with, or caused by a toxin or poison.

   a toxic condition.

2. acting as or having the effect of a poison; poisonous.

   a toxic drug.

3. causing unpleasant feelings; harmful or malicious: toxic criticism.

   a toxic boyfriend who wanted complete control over her;

   toxic criticism.

4. Finance.

   1. pertaining to or noting debt that will probably not be repaid.

      toxic mortgages.

   2. pertaining to or noting a financial instrument or other asset that has no value or an unknown value because there is no market for it.

      toxic mortgage-backed securities.

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noun

toxics plural

1. a toxic chemical or other substance.

toxic British  

/ ˈtɒksɪk /

adjective

1. of, relating to, or caused by a toxin or poison; poisonous

2. harmful or deadly

3. (of a financial asset) likely to cause significant loss to the holder

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toxic Scientific  

/ tŏk′sĭk /

1. Relating to or caused by a toxin.

2. Capable of causing injury or death, especially by chemical means; poisonous.

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Other Word Forms

Derived Forms

• hypertoxic
  adjective
• nontoxic
  adjective
• posttoxic
  adjective
• untoxic
  adjective
• nontoxically
  adverb
• toxically
  adverb
• untoxically
  adverb

Inflected Forms

Nouns

• toxics
  plural

Etymology

Origin of toxic

First recorded in 1655–65; from Late Latin toxicus “poisonous,” derivative of toxicum “poison,” from Greek toxikón (for toxikòn phármakon literally, “bow poison,” i.e., poison used on arrows), equivalent to tóx(on) “bow” + -ikon, neuter of -ikos adjective suffix; see -ic

Explanation

Danger! Hazardous! Do not eat! These are just some of the warnings you'll see on toxic substances — meaning stuff that's poisonous and even deadly. Cobra bites, wild mystery mushrooms and strong chemicals are all toxic. So are certain people, if they have particularly mean personalities. Toxic is related to the word toxin, which is a kind of poison. It comes from the ancient Greek word toxikon, which means "poison for arrows." Some toxic arrows could come in handy for those toxic personalities...

Example Sentences

Decades of tortured relations between Iran, its Middle Eastern neighbours and the US have left behind a toxic legacy, characterised by deep suspicion and an almost total lack of trust.

From BBC • Jul. 5, 2026

"I've been through it," Ceuzany said, explaining that "I gathered the strength to leave a toxic relationship" that lasted nearly five years.

From Barron's • Jul. 2, 2026

The way everyone responded to this error—by turning a simple mistake into a ritual flogging—only bolsters the toxic notion that the press is forever viciously intruding on the secret, sacred work of perfect jurists.

From Slate • Jul. 2, 2026

“The goal isn’t to be like some Italian, Brazilian, or American cities where you have entire rows, entire walls of convectors outside buildings that make an unbearable racket, releasing heat and toxic fumes,” Pulvar said.

From The Wall Street Journal • Jul. 1, 2026

Of these 67, 59 were caused by seed dressings, 8 by toxic sprays.

From "Silent Spring" by Rachel Carson

Related Words

• deadly
• harmful
• lethal
• noxious
• pernicious
• virulent