Synonyms of hazardous

hazardous

adjective

ˈha-zər-dəs 

as in dangerous

involving potential loss or injury

a hazardous journey across the arctic ice

Synonyms & Similar Words

• dangerous
• perilous
• risky
• serious
• unsafe
• precarious
• treacherous
• menacing
• unhealthy
• threatening
• venturesome
• grave
• grievous
• random
• parlous
• fatal
• harmful
• destructive
• detrimental
• jeopardizing
• uncertain
• unpleasant
• adverse
• bad
• lethal
• deadly
• insecure
• sickening
• injurious
• haphazard
• ultrahazardous
• dicey
• chance
• deleterious
• distressing
• ugly
• murderous
• malignant
• noxious
• pernicious
• nasty
• fell
• evil
• wicked
• baneful
• hurtful
• killer
• inimical
• dire
• ill
• mortal
• fateful
• deathly
• baleful
• pestilent

Antonyms & Near Antonyms

• safe
• harmless
• nonhazardous
• innocuous
• innocent
• beneficial
• nonthreatening
• good
• advantageous
• unthreatening
• ultrasafe

Synonym Chooser

How is the word hazardous distinct from other similar adjectives?

Some common synonyms of hazardous are dangerous, perilous, precarious, and risky. While all these words mean "bringing or involving the chance of loss or injury," hazardous implies great and continuous risk of harm or failure.

claims that smoking is hazardous to your health

When is dangerous a more appropriate choice than hazardous?

In some situations, the words dangerous and hazardous are roughly equivalent. However, dangerous applies to something that may cause harm or loss unless dealt with carefully.

soldiers on a dangerous mission

When could perilous be used to replace hazardous?

Although the words perilous and hazardous have much in common, perilous strongly implies the immediacy of danger.

perilous mountain roads

In what contexts can precarious take the place of hazardous?

While the synonyms precarious and hazardous are close in meaning, precarious suggests both insecurity and uncertainty.

earned a precarious living by gambling

Where would risky be a reasonable alternative to hazardous?

While in some cases nearly identical to hazardous, risky often applies to a known and accepted danger.

shied away from risky investments

Example Sentences

Recent Examples of hazardous

Dispose of dangerous items properly by contacting your local hazardous waste collection site. —Melissa Locker, Southern Living, 21 Jan. 2026

Drivers in Sacramento and other Central Valley communities could face hazardous conditions Wednesday morning due to dense fog, according to the National Weather Service. —Don Sweeney, Sacbee.com, 21 Jan. 2026

The program will help remove accumulated debris, illegally dumped materials, and hazardous substances from the site to eliminate environmental and public health risks. —Kamal Morgan, Fort Worth Star-Telegram, 21 Jan. 2026

The National Weather Service’s Fort Worth office warned of hazardous winter weather, with precipitation forecasted to start Friday before transitioning to freezing rain and sleet. —Jessica Ma, Dallas Morning News, 21 Jan. 2026