harm·ful 
/ˈhɑɚmfəl/ adjective
/ˈhɑɚmfəl/ adjective [more harmful; most harmful] : causing or capable of causing damage or harm
▪ The chemical kills harmful [=dangerous] bacteria. ▪ They claim that the drug has no harmful [=bad] side effects. — often + to ▪ These conditions can be harmful to plant/animal life.
▪ The chemical kills harmful [=dangerous] bacteria. ▪ They claim that the drug has no harmful [=bad] side effects. — often + to ▪ These conditions can be harmful to plant/animal life.
— harm·ful·ly adverb
— harm·ful·ness noun [noncount]
