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adj B2 Upper-Intermediate Uncommon

hazardous

HA-z-dihs

Hazardous (adj) means Dangerous; likely to cause harm. Example: “Workers must wear protective gear when handling hazardous chemicals.”

adj
1
Dangerous; likely to cause harm.
"Workers must wear protective gear when handling hazardous chemicals."
"Driving in that fog was hazardous."

How to use hazardous

Learner’s notes

In plain EnglishRisky or dangerous, often used for substances, conditions, or activities.

Common pairings
hazardous waste hazardous materials hazardous conditions

Word forms

more hazardous comparative, most hazardous superlative

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Test yourself on “hazardous” A quick quiz — meaning, synonyms & usage

Fill the gap

Can you complete this real example?

Workers must wear protective gear when handling _____ chemicals.

Etymology

From French hasardeux, built on "hazard" plus the adjective ending "-ous."

Origin: French

Antonyms

non-hazardous nonhazardous

Related words

Rhymes for hazardous

See all rhymes for hazardous →

Frequently asked questions

What does “hazardous” mean?

The word “hazardous” means dangerous; likely to cause harm. In plain terms, risky or dangerous, often used for substances, conditions, or activities.

How do you pronounce “hazardous”?

“Hazardous” is pronounced HA-z-dihs (/ˈhæ.zɚ.dɪs/ in IPA).

How do you use “hazardous” in a sentence?

Here is “hazardous” used in a sentence: “Workers must wear protective gear when handling hazardous chemicals.”

What is the opposite of “hazardous”?

The opposite of “hazardous” — its antonyms — are non-hazardous and nonhazardous.

What part of speech is “hazardous”?

“Hazardous” is an adjective.

Where does the word “hazardous” come from?

The word “hazardous” comes from French. From French hasardeux, built on "hazard" plus the adjective ending "-ous.".

Is “hazardous” a common word?

“Hazardous” is an uncommon word in modern English, usually learned at around the B2 level.

What is the difference between hazardous and dangerous?

Hazardous and dangerous are close synonyms, both meaning likely to cause harm, but hazardous is more often used in formal, technical, or safety contexts, such as "hazardous waste" or "hazardous materials." Dangerous is more general-purpose and used in everyday speech.

What is the difference between hazardous and toxic?

Hazardous is a broad term meaning likely to cause harm of any kind, including physical, chemical, or environmental danger, while toxic specifically refers to something poisonous. A hazardous material may or may not be toxic; it could instead be flammable, corrosive, or otherwise dangerous.

What is considered a hazardous material?

A hazardous material is any substance likely to cause harm, which can include chemicals that are flammable, corrosive, toxic, or radioactive. The term is commonly used in workplace safety, shipping, and environmental regulations to flag items requiring special handling.

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