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.

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 kidneys. …

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

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

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 © 2025 …