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Synonyms

hazardous

American  
[haz-er-duhs] / ˈhæz ər dəs /

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 British  
/ ˈhæzədəs /

adjective

  1. involving great risk

  2. depending on chance

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Other Word Forms

Etymology

Origin of hazardous

First recorded in 1570–80; hazard + -ous

Explanation

The noun "hazard" means something dangerous, and the adjective hazardous refers to anything that involves danger. A golf course with lots of sand traps is especially hazardous for golfers. That's why those traps are called hazards. If your car blows a tire in the middle of the night, make sure to turn on your hazard lights. Being invisible to other drivers is hazardous to everyone, especially yourself. Life is, by definition, hazardous. It's full of dangers, both obvious and otherwise. Acknowledge that fact and keep going anyway. If you spend all your time focusing on what's hazardous, you end up missing all the wonderful things in life.

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Vocabulary lists containing hazardous

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

But a Park Service official testified Monday that none of the trees removed Saturday had been identified as hazardous.

From Salon ● Oct. 12, 2026

Such agents help reactions proceed by accepting or donating electrons, but some can be hazardous to handle and generate unwanted waste.

From Science Daily ● Oct. 12, 2026

Florida Governor Ron DeSantis said flooding was a continued risk and warned of a "very hazardous situation".

From BBC ● Oct. 10, 2026

Under Malaysian guidelines, API readings above 100 are classified as unhealthy, above 200 as very unhealthy, above 300 as hazardous, while readings beyond 500 constitute the threshold for declaring a local emergency.

From Barron's ● Oct. 9, 2026

The long distance between a filler and a gap can be hazardous to writer and reader alike.

From "The Sense of Style" by Steven Pinker

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