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

When it comes to parallels with America’s deadliest conflict, “there’s only one lesson,” the historian said.

From Los Angeles Times

Health officials are warning about the potentially deadly dangers of a synthetic kratom compound after it was linked to three recent fatal overdoses in Los Angeles County.

From Los Angeles Times

Ms Alaqad said this has been the "deadliest" time to be a journalist in Palestine.

From BBC

Since the deadly Hamas-led attacks on Israel on 7 October 2023 triggered the brutal war in the Gaza Strip, world attention has largely been focused there.

From BBC

“Spiritual warfare rhetoric was a big part of January 6,” he said of the deadly 2021 attack on the U.S.

From Los Angeles Times

Related Words

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