Definition of harmful in US English:



  • Causing or likely to cause harm.

    ‘sugars that can be harmful to the teeth’
    ‘shield the planet from harmful cosmic rays’
    • ‘Are the more sexual representations merely offensive, or can they be genuinely harmful?’
    • ‘We learn patterns of behaviour there - some of which are useful, some of which are harmful.’
    • ‘It is not unusual to find substances in illegal drugs that are much more harmful than the drugs themselves.’
    • ‘It could be said that alcohol and tobacco are much more harmful drugs than either cocaine or heroin.’
    • ‘More drugs fail clinical tests because of harmful effects on the liver than for any other reason.’
    • ‘The Thames has highly dangerous levels of e.coli and other harmful bacteria.’
    • ‘My mother was so protective that now I feel it was actually quite harmful to me.’
    • ‘Not all these chemicals are healthy, not all are harmful, most can be either.’
    • ‘CFC gas damages the ozone layer which protects the earth from harmful rays from the sun.’
    • ‘This is a highly controversial treatment and it is suggested that it might be harmful.’
    • ‘From what I've been told smoking cannabis is allegedly less harmful than cigarettes.’
    • ‘To restrict fluid to the extent of causing dehydration may even be harmful.’
    • ‘There are alternative fuels, some less harmful to the atmosphere and some which do no harm at all.’
    • ‘Chocolate is legal and more effective and also has no harmful side-effects whatsoever.’
    • ‘Pollution on our roads is far more harmful to us all than cigarette smoke will ever be.’
    • ‘The lack of atmosphere also means there's no protection from harmful radiation in the solar wind.’
    • ‘It is the acidic environment produced by the harmful bugs that results in tooth decay.’
    • ‘The lining of the stomach produces a B acid to help digest food and also protect from harmful bacteria.’
    • ‘It is quite a harmful chemical and may produce adverse reactions.’
    • ‘High work demands and high mobilisation of efforts at work may not always indicate harmful stress.’
    damaging, injurious, detrimental, dangerous, deleterious, unfavourable, negative, disadvantageous, unhealthy, unwholesome, hurtful, baleful, wounding, destructive, environmentally unfriendly
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