Meaning & use
hazardous
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Meanings
adjectivenot comparable
Likely to cause harm, injury, or damage; dangerous.
Grammar: Used before a noun (hazardous waste) or after a linking verb (the journey was hazardous).
Patterns
- hazardous to someone/something
- hazardous for someone
- a hazardous situation
- hazardous waste
The old factory left behind hazardous chemicals that had to be cleaned up.
Driving in thick fog is hazardous for everyone on the road.
The workers wore protective suits because the fumes were hazardous to their health.
adjectivenot comparable
Involving risk or uncertainty; not safe or guaranteed.
Grammar: Often describes financial or career decisions where the outcome is unsure.
Patterns
- a hazardous investment
- hazardous to your career
- hazardous conditions
Putting all your savings into one company is a hazardous strategy.
The icy roads made the trip hazardous, so we turned back.
It would be hazardous to your reputation to ignore the complaints.
Common combinations
- hazardous waste
- Hazardous waste must be disposed of at a licensed facility.
- hazardous conditions
- The mountain rescue team warned of hazardous conditions after the storm.
- hazardous to health
- Long exposure to asbestos is hazardous to health.
- hazardous materials
- Trucks carrying hazardous materials are not allowed in the tunnel.
- a hazardous occupation
- Fishing is one of the most hazardous occupations in the world.
Synonyms and how they differ
- dangerous
- The most general word; hazardous is more formal and often used for conditions, substances, or activities that pose a recognized risk.
- risky
- Focuses on the chance of a bad outcome, especially in decisions; hazardous suggests a more concrete physical threat.
- perilous
- Literary and stronger, suggesting great and immediate danger; hazardous is more neutral and everyday.
- unsafe
- Simply means not safe; hazardous often implies a specific source of harm, such as chemicals or weather.
Opposites
Word family
- hazard noun
- A possible source of danger or harm.
- hazardously adverb
- In a dangerous or risky way (rare).
Commonly confused: hazardous or haphazard?
hazardous vs haphazard
Haphazard means disorganized or random, not dangerous. A haphazard plan is messy; a hazardous plan is risky.
Practice
The chemical is hazardous ___ human health.
Choose one answer.
"Hazardous to" is the standard pattern when saying what is at risk. "For" can sometimes be used with people (hazardous for children), but "to health" is the fixed phrase.
Make it your own
Write a sentence using “hazardous”, then check it and compare it with the examples above.