deadly

[ded-lee]

adjective

deadlier, deadliest 

1. causing or tending to cause death; fatal; lethal.

   a deadly poison.

2. aiming to kill or destroy; implacable.

   a deadly enemy.

3. like death.

   a deadly pallor.

4. excruciatingly boring.

   The dinner party was absolutely deadly.

   Synonyms: dreary, tedious, dull

5. excessive; inordinate.

   deadly haste.

6. extremely accurate.

   Annie Oakley was a deadly shot.

adverb

1. in a manner resembling or suggesting death.

   deadly pale.

2. excessively; completely.

   deadly dull.

deadly

/ ˈdɛdlɪ /

adjective

1. likely to cause death

   deadly poison

   deadly combat

2. informal,  extremely boring

adverb

1. like death in appearance or certainty

   deadly pale

   a deadly sleep

Other Word Forms

• deadliness noun
• nondeadly adjective

Word History and Origins

Origin of deadly¹

First recorded before 900; Middle English deedli(ch), Old English dēadlīce; dead, -ly

Synonym Study

See fatal.

Example Sentences

The MP is being prosecuted over comments she made on social media four years ago during deadly protests in South Africa, following the arrest of her father.

Read more on BBC

Saturday was one of the deadliest days since the US-brokered truce between Israel and Hamas came into effect, after two years of war.

Read more on Barron's

Whole city blocks were inundated last week in coastal Nha Trang, while deadly landslides struck highland passes around the Da Lat tourist hub.

Read more on Barron's

Whole sections of coastal Nha Trang city were inundated last week, while deadly landslides struck highland passes around the Da Lat tourist hub.

Read more on Barron's

Researchers at Washington University School of Medicine in St. Louis, working with scientists at Northwestern University, have created a noninvasive strategy to treat one of the most aggressive and deadly forms of brain cancer.

Read more on Science Daily

Related Words

• bloody 
• carcinogenic 
• cruel 
• dangerous 
• destructive 
• fatal 
• harmful 
• lethal 
• malignant 
• mortal 
• murderous 
• noxious 
• pernicious 
• poisonous 
• savage 
• suicidal 
• toxic 
• violent 
• virulent