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.

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

• Audio (US):

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

1. 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 the environment.

• injurious; see also Thesaurus:harmful

• beneficial
• harmless

• harmfully
• harmfulness

• harm