haz·​ard·​ous ˈha-zər-dəs How to pronounce hazardous (audio)
: involving or exposing one to risk (as of loss or harm)
a hazardous occupation
disposing of hazardous waste
: depending on the effect of unpredictable and unanalyzable forces in determining events : depending on hazard (see hazard entry 1 sense 2a) or chance
hazardous outcomes
hazardously adverb
hazardousness noun
Choose the Right Synonym for hazardous

dangerous, hazardous, precarious, perilous, risky mean bringing or involving the chance of loss or injury.

dangerous applies to something that may cause harm or loss unless dealt with carefully.

soldiers on a dangerous mission

hazardous implies great and continuous risk of harm or failure.

claims that smoking is hazardous to your health

precarious suggests both insecurity and uncertainty.

earned a precarious living by gambling

perilous strongly implies the immediacy of danger.

perilous mountain roads

risky often applies to a known and accepted danger.

shied away from risky investments

Examples of hazardous in a Sentence

It was a hazardous voyage. These are hazardous chemicals that can cause death if inhaled.
Recent Examples on the Web There was a tree stump that a Tengu goblin had sat upon, and an RIP stone memorial honoring black cattle who died hauling cargo over these hazardous hillsides. Norma Meyer, Orange County Register, 15 May 2024 Immigrant workers may also be less likely to decline a hazardous task or report an unsafe work environment, the study says. Ames Alexander, Charlotte Observer, 15 May 2024 See all Example Sentences for hazardous 

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'hazardous.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


see hazard entry 1

First Known Use

1549, in the meaning defined at sense 1

Time Traveler
The first known use of hazardous was in 1549

Dictionary Entries Near hazardous

Cite this Entry

“Hazardous.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/hazardous. Accessed 24 May. 2024.

Kids Definition


haz·​ard·​ous ˈhaz-ərd-əs How to pronounce hazardous (audio)
hazardously adverb
hazardousness noun

Legal Definition


: creating a hazard : involving or exposing one to risk (as of loss or harm)
a hazardous occupation
a hazardous substance
hazardously adverb

More from Merriam-Webster on hazardous

Last Updated: - Updated example sentences
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