deadly

adjective
dead·​ly | \ ˈded-lē How to pronounce deadly (audio) \
deadlier; deadliest

Definition of deadly

 (Entry 1 of 2)

1 : likely to cause or capable of producing death deadly poison
2a : aiming to kill or destroy : implacable a deadly enemy
b : highly effective a deadly exposé
c : unerring a deadly marksman
d : marked by determination or extreme seriousness
3a : tending to deprive of force or vitality a deadly habit
b : suggestive of death especially in dullness or lack of animation deadly bores a deadly conversation
4 : very great : extreme

deadly

adverb

Definition of deadly (Entry 2 of 2)

1 archaic : in a manner to cause death : mortally
2 : suggesting death
3 : extremely deadly serious

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Other Words from deadly

Adjective

deadliness noun

Choose the Right Synonym for deadly

Adjective

deadly, mortal, fatal, lethal mean causing or capable of causing death. deadly applies to an established or very likely cause of death. a deadly disease mortal implies that death has occurred or is inevitable. a mortal wound fatal stresses the inevitability of what has in fact resulted in death or destruction. fatal consequences lethal applies to something that is bound to cause death or exists for the destruction of life. lethal gas

Adjective

deadly, mortal, and fatal mean causing or capable of causing death. deadly is used of something that is certain or very likely to cause death. The mushroom contains a deadly poison. mortal is used of something that already has caused death or is about to cause death. He received a mortal wound in battle. fatal is used when death is certain to follow. The wounds proved to be fatal.

Examples of deadly in a Sentence

Adjective

the world's most deadly snake a more deadly form of the disease They launched a deadly attack. Officers are allowed to use deadly force if necessary. She shoots with deadly accuracy. a basketball player with deadly aim A deadly silence followed his question. The two gang leaders are deadly enemies. He spoke with deadly seriousness.

Adverb

I'm deadly serious about making an offer on the house.
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Recent Examples on the Web: Adjective

Within hours the British authorities determined the pair had been exposed to a deadly chemical weapon. Elisabeth Braw, WSJ, "How the British Hit Back Against Russian Agitprop," 11 Mar. 2019 But miscalculations and assumptions could prove deadly. David Hambling, Popular Mechanics, "What You Need to Know About the South China Sea, the World's Next Hot Spot," 27 Feb. 2019 Witty and deadly serious, High Flying Bird is preoccupied with what we're all preoccupied with 2019: capitalism, work, social justice, race. Taylor Antrim, Vogue, "Why Netflix's High Flying Bird Feels Like The Future of Movies," 8 Feb. 2019 Bladder cancer is among the most common and deadly of cancers. Diana Gitig, Ars Technica, "Just pee in a cup for bladder cancer detection," 10 Dec. 2018 While turkey vultures are common in Indiana, black vultures are a relatively new and deadly arrival. Jordyn Hermani, Indianapolis Star, "Black vultures are eating cows alive. But it's difficult to legally kill the birds.," 13 July 2018 And migration has proved dangerous and even deadly for those on the move. Megan Specia, New York Times, "U.N. Agrees on Migration Pact, but U.S. Is Conspicuously Absent," 13 July 2018 The charges include allegations of a prior conviction, causing great bodily injury and using a deadly and dangerous weapon. Brittny Mejia, latimes.com, "Man charged with murder, attempted murder in connection with West Hollywood knife attack," 12 July 2018 Wednesday’s attack, the deadliest in Sistan and Baluchistan in years, is the latest eruption of sectarian violence in Iran. Sune Engel Rasmussen, WSJ, "Suicide Bombing Kills Revolutionary Guards in Restive Iranian Province," 13 Feb. 2019

Recent Examples on the Web: Adverb

Schlenk used his next two picks with that in mind: Maryland’s Kevin Huerter (deadly from the outside) and Villanova forward Omari Spellman, who plays a creative offensive game and can hit the three-pointer. Bruce Jenkins, SFChronicle.com, "As the Warriors go their way, the big men multiply," 23 June 2018 OLYMPIA — Community advocates, law-enforcement groups and state lawmakers are vowing to quickly approve the compromise legislation that was thrown out by the courts earlier this year to change Washington’s police deadly-use-of-force law. Joseph O’sullivan, The Seattle Times, "Community advocates, law enforcement groups call for Legislature to pass compromise bill on police deadly force," 3 Dec. 2018 The economic consequences of peace were deadly, and the astronomic reparations Berlin was forced to pay continued to sabotage its economic recovery. Josef Joffe, WSJ, "Is Germany Slouching Toward Weimar Again?," 23 Sep. 2018 In Charlottesville, Virginia, marking one year since a white nationalist rally turned deadly. Fox News, "Diamond & Silk sound off on Chicago violence," 12 Aug. 2018 The on-again, off-again summit meeting scheduling had all the earmarks of a television cliffhanger from a president who made a name for himself hosting a reality show on NBC for 14 years, only this time there were deadly serious consequences. Peter Baker, New York Times, "Trump Announces Summit Meeting With Kim Jong-un Is Back on," 1 June 2018 The night turned deadly at about 11 p.m. when police were called to the 1600 block of Pentwood Road in Northeast Baltimore. Lauren Lumpkin, baltimoresun.com, "2 killed, 2 injured in overnight shootings in Baltimore," 8 July 2018 In some cases, that abuse turns deadly: On average, between four and seven American children die each day because of abuse and neglect. Gaby Del Valle, Teen Vogue, "How Child Abuse Affects the Brain," 22 June 2018 Nightmare bacteria — those that are resistant to almost every drug — are particularly deadly in the elderly and people with chronic illnesses. Liz Szabo, Washington Post, "‘Nightmare Bacteria’ Stalk U.S. Hospitals," 3 Apr. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'deadly.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of deadly

Adjective

before the 12th century, in the meaning defined at sense 1

Adverb

before the 12th century, in the meaning defined at sense 1

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Statistics for deadly

Last Updated

17 Mar 2019

Look-up Popularity

Time Traveler for deadly

The first known use of deadly was before the 12th century

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More Definitions for deadly

deadly

adjective

English Language Learners Definition of deadly

 (Entry 1 of 2)

: causing or able to cause death
: extremely accurate and effective
: extreme or complete

deadly

adverb

English Language Learners Definition of deadly (Entry 2 of 2)

: extremely or completely

deadly

adjective
dead·​ly | \ ˈded-lē How to pronounce deadly (audio) \
deadlier; deadliest

Kids Definition of deadly

 (Entry 1 of 2)

1 : causing or capable of causing death deadly poisons
2 : meaning or hoping to kill or destroy deadly enemies
3 : very accurate He shot the arrow with deadly aim.

deadly

adverb

Kids Definition of deadly (Entry 2 of 2)

1 : in a way suggestive of death Her face was deadly pale.
2 : to an extreme degree deadly dull

deadly

adjective
dead·​ly | \ ˈded-lē How to pronounce deadly (audio) \
deadlier; deadliest

Medical Definition of deadly

: likely to cause or capable of causing death a deadly disease a deadly poison a deadly instrument

Other Words from deadly

deadliness \ -​nəs How to pronounce deadliness (audio) \ noun

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deadly

adjective
dead·​ly
deadlier; deadliest

Legal Definition of deadly

: likely to cause or capable of causing death also : dangerous sense 2

Note: Deadly and dangerous are sometimes used interchangeably, especially in connection with weapons or instruments.

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More from Merriam-Webster on deadly

Rhyming Dictionary: Words that rhyme with deadly

Thesaurus: All synonyms and antonyms for deadly

Spanish Central: Translation of deadly

Nglish: Translation of deadly for Spanish Speakers

Britannica English: Translation of deadly for Arabic Speakers

Comments on deadly

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