haz·ard·ous | \ˈha-zər-dəs \

Definition of hazardous 

1 : depending on the effect of unpredictable and unanalyzable forces in determining events : depending on hazard (see hazard entry 1 sense 3a) or chance hazardous outcomes

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

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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

Part of the Coral Ridge Isles neighborhood was closed to traffic while a hazardous-materials team and a bomb-and-arson squad robot checked the house. Wayne K. Roustan, Sun-Sentinel.com, "Two arrested, pot plants seized, officers recovering after two raids," 13 July 2018 Under those standards, the fire department should have planned for a hazardous materials emergency at the fertilizer plant, but hadn’t done so. Mike Hendricks, kansascity, "Firefighters protect us. Who protects them?," 13 July 2018 Though lava flows aren’t as hazardous, they should still be taken seriously. Alessandra Potenza, The Verge, "Falling into lava would be a pretty hot mess," 30 May 2018 Also like laze, breathing vog can be hazardous to your health, and Hawaii officials and the Joint Task Force 5-0 are keeping a close watch on local air quality. Maya Wei-haas, Smithsonian, "A Brief Glossary of Volcano Vocab," 25 May 2018 Despite the potentially hazardous situation, police told the outlet passengers were never in any danger. Benjamin Brown, Fox News, "American tourist allegedly tries to take 'souvenir' WWI artillery shell on plane," 11 July 2018 This weekend’s multi-day heat wave is also expected to result in high levels of potentially hazardous ozone air pollution in Connecticut. courant.com, "Brutal Heat Ahead, But Bacteria Could Close Four State Beaches This Weekend," 29 June 2018 Once satellites reach orbit, the new system is intended to save fuel by reducing maneuvers necessary to skirt potentially hazardous debris. Andy Pasztor, WSJ, "White House Issues Strategies to Combat Growing Orbital Debris Risks," 19 June 2018 But inside the home, firefighters found potentially hazardous lab equipment and flammable chemicals in almost every room. Alene Tchekmedyian, latimes.com, "A drug lab in Lake Elsinore exploded in November. The ex-cop behind it was just sentenced 5 years in prison," 19 June 2018

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 2

History and Etymology for hazardous

see hazard entry 1

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Statistics for hazardous

Last Updated

5 Oct 2018

Look-up Popularity

Time Traveler for hazardous

The first known use of hazardous was in 1549

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More Definitions for hazardous



English Language Learners Definition of hazardous

: involving risk or danger


haz·ard·ous | \ˈha-zər-dəs \

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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