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 The order spells out milestones the lab needs to meet with its cleanup campaigns and establishes corrective actions for the release of hazardous wastes or groundwater contamination. USA TODAY, "Surfing Santas, endangered red wolves, who owns the letter ‘O’?: News from around our 50 states," 28 Dec. 2019 Many municipalities have hazardous-waste disposal facilities that will take it. Mike Allen, Popular Mechanics, "How to Flush Your Radiator and Cooling System," 11 Dec. 2019 And in August, the Environmental Protection Agency prohibited health care facilities from flushing down the drain pharmaceuticals regarded as hazardous waste, such as chemotherapy drugs. Natasha Gilbert, STAT, "‘Dump it down the drain’: How contaminants from prescription-drug factories pollute waterways," 11 Dec. 2019 The agency is neutral about the future of nuclear, seen by some as a beneficial, carbon-free energy source and others as high-risk energy with long-lasting, hazardous waste. Nora G. Hertel, Twin Cities, "Inspectors monitor Monticello nuclear plant, which has a lot of life left in it," 8 Dec. 2019 The US Supreme Court will this week hear oral arguments in a high-stakes case about corporations, hazardous waste, and paying to clean up pollution. Ephrat Livni, Quartz, "ARCO is taking a fight over toxic-waste cleanup to the US Supreme Court," 30 Nov. 2019 The wells are considered a lower priority for enforcement than others that store hazardous waste from mining, oil and gas, Reeverts said. Lisa Song, ProPublica, "MIT Media Lab Kept Regulators in the Dark, Dumped Chemicals in Excess of Legal Limit," 20 Sep. 2019 Firefighters in Methuen are getting some added protection from exposure to potentially hazardous chemicals due to a pair of new state grant awards. John Laidler, BostonGlobe.com, "Methuen firefighters getting new protective gear," 7 Jan. 2020 Shoup during the trial said sulfolane was not considered a hazardous chemical by the state and was not a regulated chemical at the time of the spill. Dan Joling, Anchorage Daily News, "Former owner of North Pole refinery ordered to pay over $29 million in water pollution case," 4 Jan. 2020

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

26 Jan 2020

Cite this Entry

“Hazardous.” The Merriam-Webster.com Dictionary, Merriam-Webster Inc., https://www.merriam-webster.com/dictionary/hazardous. Accessed 26 January 2020.

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More Definitions for hazardous


How to pronounce hazardous (audio)

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

What made you want to look up hazardous? Please tell us where you read or heard it (including the quote, if possible).


to express in a more acceptable way

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