deadly

adjective
dead·​ly | \ˈded-lē \
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

As news spread about the deadly encounter at Sibuya Game Reserve, some conservationists and others expressed approval that poachers may have received due punishment from the lions. Lindsey Bever, latimes.com, "Poachers were looking for rhinos. They found hungry lions instead, game reserve says," 6 July 2018 The deadly encounter took place sometime after 3:30 a.m. outside Corning, N.Y., on a secluded, dead-end road not far from the Pennsylvania state line, in Steuben County. Joseph Goldstein, New York Times, "Trooper Is Killed Answering Call to Home of School Principal," 2 July 2018 The deadly encounter was captured on the gas station's surveillance cameras. Robert A. Cronkleton, kansascity, "Short argument sparks fatal shooting at Independence gas station, owner says," 24 June 2018 He was sworn in less than two hours before the deadly encounter. CBS News, "4 arrested amid protests over fatal police shooting of Antwon Rose Jr.," 23 June 2018 There were those in the community who saw Eddie Patterson as another Mark Barmore—an unarmed black man in a deadly encounter with a cop. Ben Austen, The New Republic, "How one American city chose to tackle crime, combat racism, and reckon with the legacy of police brutality," 21 June 2018 Video of the deadly encounter has been making the rounds online. National Geographic, "Python Swallows Woman Whole—What Experts Say About the Rare Attack," 18 June 2018 But, in recent years, as deadly encounters with police have attracted more attention —particularly on social media — cities such as Milwaukee are requiring all officers to complete the training. Milwaukee Journal Sentinel, "Implementation of mental health training plan for officers runs counter to recommendations," 8 June 2018 No Brightline train has been found at fault in any of the deadly encounters. David J. Neal, miamiherald, "Seventh fatality involving a Brightline train looks like a suicide, cops say," 4 June 2018

Recent Examples on the Web: Adverb

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 When that rally turned deadly, Trump was slow to condemn racist demonstrators. David Z. Morris, Fortune, "Airbnb Has Some Breathtaking Listings in ‘Shithole’ Countries," 14 Jan. 2018 This is a show where, more than once, the performer makes the crowd laugh and laugh and, suddenly, turn deadly silent. Jason Zinoman, New York Times, "Introducing a Major New Voice in Comedy (Who Also Attacks Comedy)," 19 Mar. 2018 The rise and fall of the 111-year-old rowhouse, traced through interviews, deeds, court records and inspection reports, reveals the story of Baltimore, and its blight — how good homes come to ruin, and how one turned deadly. Tim Prudente, baltimoresun.com, "Collapse: The rise and deadly fall of a Baltimore rowhouse," 12 July 2018 Including the kind that draw warnings from critics that arming school personnel could turn deadly. Washington Post, "Texas educators training to shoot back at school shooters," 29 June 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

10 Nov 2018

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 \
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 \
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 \ 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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Comments on deadly

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