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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.

Hazardous rip currents and elevated surf are also expected at Los Angeles County beaches and along the Malibu coast, forecasters said.

From Los Angeles Times • May 15, 2026

Robin Bidgood, member of the Welsh Ambulance Service's Hazardous Area Response Team, told Leah he was "amazed" that she was alive and in front of him talking.

From BBC • Mar. 18, 2026

Sable’s permit from the Transportation Department’s Pipeline and Hazardous Materials Safety Administration, or PHMSA, waived the requirement to evaluate and remedy corrosion in the pipeline.

From Barron's • Jan. 2, 2026

Hazardous materials such as asbestos, broken fittings and other non-recyclable items are disposed of separately.

From The Wall Street Journal • Dec. 9, 2025

Hazardous as it had been hitherto for a man of his condition to engage in single combat it was rendered doubly so by this exposure, offered to the public as an aristocratic apologia.

From Scaramouche by Sabatini, Rafael

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