harmful

harmful
harm‧ful /ˈhɑːmfəl $ ˈhɑːrm-/ adjectivecausing harm:
    the harmful effects of smoking
    harmful to
    chemicals that are harmful to the environment
     

THESAURUS

   ▪ harmful causing physical harm – used especially about things that cause harm to your health, the environment etc: Smoking is harmful to your health. | drugs with harmful side-effects
   ▪ be bad for somebody/something to have a harmful effect on someone or something. This phrase is very commonly used in everyday English when saying that something is harmful: Everyone knows that too much alcohol is bad for you.
   ▪ damaging used about things that cause permanent physical harm, or that have a bad effect in other ways, for example on people’s opinion of someone: Acid rain has a damaging effect on trees and the soil. | The allegations were very damaging to his career. | Constant criticism is damaging to a child’s self-esteem.
   ▪ detrimental formal causing harm or having a bad effect on something: Employers are worried that the new laws will have a detrimental effect on their business. | chemicals that are detrimental to the environment | policies that have been detrimental to the interests of old people
   ▪ negative a negative effect is one that is bad and causes problems: The car tax had a negative effect on car sales. | the negative impact of the recession in the US
   ▪ hazardous hazardous substances are likely to be dangerous to people’s health and safety: Hazardous waste needs to be disposed of safely. | hazardous chemicals
   ▪ toxic toxic substances, smoke etc are poisonous: toxic waste | toxic fumes | Toxic chemicals spilled into the river.
   ▪ pernicious /pəˈnɪʃəs $ pər-/ formal used about something that has a gradual bad effect which is not easy to notice, especially on people’s morals, or on their health: the pernicious effects of violent video games | the pernicious effect of secondhand smoke