harmful

• harmfull (archaic)

From Middle English harmful, from Old English *hearmful (suggested by hearmfullīċ (“harmful; hurtful”)), equivalent to harm +‎ -ful.

Cognate with German harmvoll, Danish harmfuld, Swedish harmfull.

• (General American) IPA^(key): /ˈhɑɹmfl̩/
• (Received Pronunciation) IPA^(key): /ˈhɑːmfl̩/

• Audio (US)

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harmful (comparative harmfuller or more harmful, superlative harmfullest or most harmful)

1. of a kind likely to be damaging; injurious

   Wear a hat to protect your skin from harmful sunlight.

• Nouns to which "harmful" is often applied: effect, consequence, impact, influence, emission, chemical, ingredient, substance, gas, agent, additive, drug, radiation, dust, organism, plant, animal, insect, action, act, behavior, component, content, activity, interference, use.

• injurious; see also Thesaurus:harmful

• beneficial
• harmless

• harm