HAZARDOUS Synonyms: 66 Similar and Opposite Words

Q: 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

Q: 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

Q: 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

Q: 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

Q: 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

hazardous

adjective

ˈha-zər-dəs

Definition of hazardous

as in dangerous

involving potential loss or injury a hazardous journey across the arctic ice

Synonyms & Similar Words

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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

Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.

Recent Examples of hazardous At least 60 people were being treated for unspecified symptoms after an incident at Toledo, Ohio, business led to the release of a hazardous chemical, city officials said Wednesday. — ABC News, 21 Oct. 2026 Crews had to deal with hazardous materials, runoff and the threat of more explosions while searching for victims. — Rebekah Riess, CNN Money, 21 Oct. 2026 The building was evacuated, and police and hazardous materials teams were on the scene on Wednesday afternoon. — Sara Tenenbaum, CBS News, 21 Oct. 2026 The report does not quantify a group-wide reduction in hazardous chemical use or pollution. — Alexandra Harrell, Footwear News, 20 Oct. 2026 See All Example Sentences for hazardous

Recent Examples of Synonyms for hazardous

Adjective

In November 2021, crew members took shelter inside their spacecraft after a Russian anti-satellite weapons test created a dangerous cloud of debris.

— Kurt Knutsson, FOXNews.com, 25 Oct. 2026
In 2015, Chicago’s public health department identified three cases of invasive meningococcal disease, a highly dangerous pathogen that can kill within hours.

— Julie Morita, Time, 25 Oct. 2026

Definition of dangerous

Adjective

Christopher Nolan’s recent film reminded me of another time when the world was awash in ambiguity and leaders needed to navigate the perilous voyage across unfamiliar territory.

— Jeff DeGraff, Fortune, 17 Oct. 2026
Two Utah residents who hiked Mount Shasta in Northern California were rescued after they became stranded during a perilous 36-hour journey through freezing conditions.

— Tony Briscoe, Los Angeles Times, 17 Oct. 2026

Definition of perilous

Adjective

Revenue bonds are generally viewed as riskier than other types of government bonds, in part because they’re backed by the promise of revenue from a specific project — in this case, payment by individual borrowers.

— Audrey McGlinchy, Los Angeles Times, 24 Oct. 2026
The pain has been felt most acutely in the riskier credits with high-yield spreads rising about 70 basis points since late September.

— Justin Zacks, CNBC, 23 Oct. 2026

Definition of risky

Adjective

The Tallahassee Police Department said in a statement that 11 of the 12 were shot and that three victims had serious injuries, with one minor in serious condition.

— Samantha Cookinham, NBC news, 25 Oct. 2026
Bake this classic all the way through for a light and tender crumb, or cut the bake time short for serious gooey goodness in the center.

— Mary Shannon Wells, Southern Living, 25 Oct. 2026

Definition of serious

Adjective

Checking plans before execution The team also developed a defense system called PROTEA, designed to identify unsafe actions before a robot carries them out.

— Neetika Walter, Interesting Engineering, 21 Oct. 2026
The meat may have been stored in a refrigerator experiencing unsafe deviations in temperature.

— Eva Flowe October 21, Charlotte Observer, 21 Oct. 2026

Definition of unsafe

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hazarding

hazardous

hazards

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“Hazardous.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/hazardous. Accessed 28 Oct. 2026.

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Synonyms of hazardous

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