harmful

[hahrm-fuhl]

adjective

1. causing or capable of causing harm; injurious.

   a harmful idea;

   a harmful habit.

   Synonyms: deleterious, damaging, detrimental, hurtful
   Antonyms: beneficial

harmful

/ ˈhɑːmfʊl /

adjective

1. causing or tending to cause harm; injurious

Other Word Forms

• harmfully adverb
• harmfulness noun
• quasi-harmful adjective
• quasi-harmfully adverb
• unharmful adjective
• unharmfully adverb

Word History and Origins

Origin of harmful¹

First recorded before 1000; Middle English; Old English hearmful; harm, -ful

Example Sentences

The update will result in posts encouraging potentially harmful behavior such as "risky challenges" to be hidden from view and dropped from recommendations, according to Instagram.

Read more on Barron's

The next steps are to find a way to neutralize the harmful protein and test if this can reduce VT burden and infarct size.

Read more on Science Daily

The pharmacists' watchdog has promised to investigate and "take action" after the BBC exposed illegal and potentially harmful practices in the aesthetic Botox industry.

Read more on BBC

All England players, including age-grade squads, are trained in being "active bystanders" to intervene and protect others from harmful behaviour.

Read more on BBC

But this discovery, the scientists say, could be used to help manage harmful levels of stress.

Read more on BBC

Related Words

• adverse 
• bad 
• catastrophic 
• damaging 
• destructive 
• detrimental 
• disadvantageous 
• disastrous 
• inimical 
• noxious 
• painful 
• pernicious 
• risky 
• ruinous 
• sinful 
• toxic 
• unhealthy 
• unsafe