hazardous

[haz-er-duhs]

adjective

1. full of risk; perilous; risky.

   a hazardous journey.

   Synonyms: unsafe, dangerous
   Antonyms: secure, safe

2. dependent on chance.

   Synonyms: speculative, risky, uncertain, chancy
   Antonyms: sure, reliable, certain

hazardous

/ ˈhæzədəs /

adjective

1. involving great risk

2. depending on chance

Other Word Forms

• hazardously adverb
• hazardousness noun
• nonhazardous adjective
• nonhazardously adverb
• nonhazardousness noun
• ultrahazardous adjective
• unhazardous adjective
• unhazardously adverb

Word History and Origins

Origin of hazardous¹

First recorded in 1570–80; hazard + -ous

Example Sentences

More than 100 firefighters and a hazardous materials team are working to combat a fire involving lithium ion batteries and prototype cars at General Motors’ design studio in Pasadena, authorities said.

Read more on Los Angeles Times

China’s lax environmental standards mean it can process rare earths at lower cost and larger scale than Western countries that have rules against dumping hazardous byproducts.

Read more on The Wall Street Journal

There is no unified definition of a child or child labour in Pakistan, although a federal law prohibits children under the age of 14 from working in unsafe and hazardous environments, such as factories.

Read more on Barron's

Detecting the drones, making them non-operational by jamming them, or even shooting them down, are all complex and hazardous tasks.

Read more on Barron's

Publicly, the industry has minimized research that has identified hazardous levels of toxins in cabin air linked to fume events and their health risks.

Read more on The Wall Street Journal

Related Words

• dicey 
• difficult 
• perilous 
• precarious 
• risky 
• uncertain 
• unhealthy 
• unsafe 
• unsound