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

The drivers had been kept on the payroll even though Uber suspended its self-driving tests in North America following the deadly March 19th crash in Arizona. Andrew J. Hawkins, The Verge, "Uber laid off its self-driving car safety drivers in Pittsburgh," 11 July 2018 Three members of a Gwinnett County assistant principal’s family have been identified as the victims in a deadly weekend crash on I-75 South in Tennessee. Steve Burns, ajc, "BREAKING: Gwinnett principal’s family ID’d as victims in deadly Tennessee crash," 11 July 2018 Buy Photo Authorities have identified the man who was killed when a SEPTA bus slammed into a North Philadelphia home, and say the circumstances of the deadly crash remains under investigation. Katherine Nails, Philly.com, "Police ID man killed when SEPTA bus crashed into home, investigation continues," 6 July 2018 The morning after the deadly plane crash, the grieving volleyball team gathered in a quiet corner in the Greektown Casino Hotel lobby. Jeff Seidel, Detroit Free Press, "Volleyball player finds light in darkness on court after deadly crash," 1 July 2018 In charging documents filed Saturday in Jackson County Circuit Court, police say their investigation led them to Robinson as the driver in the deadly crash at 11th and Charlotte streets. Max Londberg, kansascity, "Police say driver was texting when he allegedly struck, killed KC man using wheelchair," 28 June 2018 Concrete girders under the Cloverdale overpass, damaged by fire from a deadly crash on June 16, display pink coloration that is a sign of internal damage. Kevin Davenport, idahostatesman, "How a 20-minute fire in the fatal I-84 crash ruined a concrete overpass," 22 June 2018 Airboat operators carrying passengers on their boats will soon have more stringent requirements to pilot their vessels, after a deadly crash that killed a University of Miami graduate last year. Elizabeth Koh, miamiherald, "FWC sets new requirements for airboat operators, spurred by death of UM grad," 22 June 2018 Saturday's fatal collision came less than two weeks after another deadly crash involving a pedestrian in Anchorage. Alex Demarban, Anchorage Daily News, "Search continues for blue pickup in hit-and-run that killed Anchorage woman," 21 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

18 Aug 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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