The meaning of HARMFUL is of a kind likely to be damaging : injurious. How to use harmful in a sentence.

You do not suppress free speech; you eliminate harmful opinions, obscenity and corruption.

Harmful definition: causing or capable of causing harm; injurious.. See examples of HARMFUL used in a sentence.

Definition of harmful adjective in Oxford Advanced Learner's Dictionary. Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and more.

harmful If something is harmful to someone or harmful for them, it has a bad effect on them. Too much salt can be harmful to a young baby. Potassium could be harmful for those with impaired …

harm•ful /ˈhɑrmfəl/ adj. causing or capable of causing harm. harm•ful•ly, adv. harm•ful•ness, n. [uncountable] WordReference Random House Unabridged Dictionary of American English © …

Oct 8, 2025 · Causing or likely to cause harm or damage; injurious. Wear a hat to protect your skin from harmful sunlight. Smoking is harmful to the lungs. Burning fossil fuels is harmful to …

Harmful is an adjective that comes in handy when you're talking about things that cause injury to someone or damage something. Burning coal can be harmful to the environment, and eating …

Something that is harmful has a bad effect on something else, especially on a person's health. ...the harmful effects of smoking.

The chemical kills harmful [= dangerous] bacteria. They claim that the drug has no harmful [= bad] side effects. These conditions can be harmful to plant/animal life.