hazardous

adjective

haz·​ard·​ous ˈha-zər-dəs 

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

hazardously adverb

hazardousness noun

Synonyms

• dangerous
• grave
• grievous
• jeopardizing
• menacing
• parlous
• perilous
• risky
• serious
• threatening
• unhealthy
• unsafe
• venturesome

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

Even as the cause of Mr. Grant’s death remains unknown, advocates of prison safety say that the strikes are creating hazardous conditions for inmates and warn that more deaths may occur if the labor dispute is not quickly resolved. —Jay Root, New York Times, 24 Feb. 2025

North Carolina is also experiencing hazardous winter conditions, with an advisory in effect until 10 a.m. EST Friday for areas including Person, Granville, Vance, Warren, and surrounding counties. —Tom Rogers, Newsweek, 21 Feb. 2025

My colleague Tony Briscoe reports that federal officials are skimping on soil testing meant to protect families from hazardous chemicals in the wake of the Palisades and Eaton fires, seemingly to speed up rebuilding. —Sammy Roth, Los Angeles Times, 20 Feb. 2025

The snow could create hazardous driving conditions on untreated roads. —Laura Barrero, Axios, 19 Feb. 2025

Word History

Etymology

see hazard entry 1

First Known Use

1549, in the meaning defined at sense 1

Rhymes for hazardous

• nonhazardous

Kids Definition

hazardous

adjective

haz·​ard·​ous ˈhaz-ərd-əs 

: dangerous sense 1, risky

hazardously adverb

hazardousness noun

Legal Definition

hazardous

adjective

haz·​ard·​ous

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

a hazardous occupation

a hazardous substance

hazardously adverb