Definition of hazardous in English:



  • Risky; dangerous:

    ‘we work in hazardous conditions’
    ‘it is hazardous to personal safety’
    • ‘Staying in a hot tub or hot spring too long may be very hazardous to your health.’
    • ‘He has been asked whether emissions from the refinery are hazardous to human health.’
    • ‘They replaced a decaying wooden Celtic cross that was in a dangerous and hazardous state.’
    • ‘Gale force winds made driving conditions hazardous and caused traffic chaos in parts of the region today.’
    • ‘Trees used to be considered hazardous to farming, and in many cases they still are.’
    • ‘He made a fantastic landing in hazardous conditions.’
    • ‘A contractor will remove ragwort, which is hazardous to many animals.’
    • ‘Always clear up after a fireworks party - litter is hazardous to domestic and wild animals.’
    • ‘He added that it would be wrong to assume that mobile phones were hazardous to human health.’
    • ‘Just sitting down near an open window can be hazardous to your health.’
    • ‘The plan is to reduce the danger posed by hazardous hemlock trees which grow in abundance on the North Shore.’
    • ‘I will not explain the procedure since it may be hazardous to some motherboards.’
    • ‘Hairdressing is one of the occupations most hazardous to the skin.’
    • ‘Workers said yesterday that they were entitled to these wages because of the hazardous nature of their jobs.’
    • ‘In the home garden it is now possible to substitute these highly toxic chemicals for ones that are less hazardous.’
    • ‘Running away was less dangerous than rebellion, but it was still a hazardous enterprise.’
    • ‘Waste can harm the environment and be hazardous to wildlife.’
    • ‘Much of the waste found on the beaches is fishing waste that can be extremely hazardous to wildlife.’
    • ‘Lightening is much more hazardous to the farmer working alone in his field than a person in a crowded city street.’
    • ‘At least one candidate in the election reports that campaigning has proven hazardous to his health.’
    chancy, uncertain, undependable, unpredictable, precarious, speculative
    dangerous, risky, unsafe, perilous, precarious, insecure, tricky, unpredictable, uncertain, high-risk, touch-and-go, fraught with danger
    View synonyms


Mid 16th century: from French hasardeux, from hasard chance (see hazard).