haz·​ard·​ous | \ ˈha-zər-dəs How to pronounce hazardous (audio) \

Definition of hazardous

1 : involving or exposing one to risk (as of loss or harm) a hazardous occupation disposing of hazardous waste
2 : 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

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Other Words from hazardous

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 Disposing of industrial, military, nuclear and other hazardous waste was a pervasive global practice in the 20th century, according to researchers. Julie Watson, chicagotribune.com, "Scientists find what they believe to be massive underwater toxic waste dump containing DDT off the California coast," 27 Apr. 2021 For example, are there issues related to its ownership of contaminated land, disposal of hazardous waste, management of toxic emissions, or compliance with government environmental regulations? Mary Josephs, Forbes, "Every Family-Owned Company And ESOP Should Consider ESG," 19 Apr. 2021 There also will be a spring household hazardous waste roundup May 10-15 for residents only. Carol Kovach, cleveland, "Spring cleanup, Trash to Treasure contest highlight Earth Day observances in Westlake, Rocky River: West Shore Chatter," 19 Apr. 2021 Lemon Grove residents are invited to dispose of household hazardous waste from 9 a.m.-1 p.m. Saturday. Laura Groch, San Diego Union-Tribune, "South/East County Happenings, April 18," 18 Apr. 2021 The inspector-general report determined the EPA has failed to adequately monitor about half of the country’s nonoperational hazardous-waste storage sites, known as Treatment, Storage, and Disposal Facilities (TSDFs). Andrew Stuttaford, National Review, "Climate and Central Banks: Regulators Doing What They Shouldn’t," 17 Apr. 2021 Parks officials said workers will tackle more than a dozen separate projects during the restoration, including planting new grass and hundreds of shrubs, removing hazardous waste, repairing damage from fires and reinstalling dozens of park benches. oregonlive, "Downtown Portland parks at center of racial justice protests to undergo $150k restoration," 13 Apr. 2021 For decades, that hazardous waste was disposed of in two ways. Jeff Berardelli, CBS News, "How a shocking environmental disaster was uncovered off the California coast after 70 years," 12 Apr. 2021 Crews will not take the following items: appliances, tires, TVs and other electronics (such as computers, printers, scanners, tablets, etc.), construction debris, paint and paint thinner, motor oil and other hazardous waste. Sophie Carson, Milwaukee Journal Sentinel, "Milwaukee collection crews will pick up large items like furniture, mattresses and yard debris in the next month," 12 Apr. 2021

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'hazardous.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of hazardous

1549, in the meaning defined at sense 1

History and Etymology for hazardous

see hazard entry 1

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Time Traveler for hazardous

Time Traveler

The first known use of hazardous was in 1549

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Statistics for hazardous

Last Updated

30 Apr 2021

Cite this Entry

“Hazardous.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/hazardous. Accessed 7 May. 2021.

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More Definitions for hazardous



English Language Learners Definition of hazardous

: involving risk or danger


haz·​ard·​ous | \ ˈha-zər-dəs How to pronounce hazardous (audio) \

Kids Definition of hazardous

: dangerous sense 1 hazardous chemicals



Legal Definition of hazardous

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

Other Words from hazardous

hazardously adverb

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Comments on hazardous

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