Definition of harmful in English:

harmful

adjective

  • Causing or likely to cause harm.

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

harmful

/ˈhɑːmfʊl/ /ˈhɑːmf(ə)l/