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

Keep scrolling for more

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.
See More

Recent Examples on the Web: Adjective

The deadly disease, formerly known as Ebola haemorrhagic fever, was originally passed to humans by animals. Sally Hayden, Time, "Inside the Battle to Save Congo From the Ebola Crisis," 19 June 2019 This is the 10th deadly shooting in the city in the past three weeks, according to police. Sarah Brookbank, Cincinnati.com, "An 18-year-old was killed in Cincinnati's 10th fatal shooting in 3 weeks," 19 June 2019 The deadliest and most destructive wildfire in California history is the Camp Fire, which broke out in November 2018 and devastated the town of Paradise in Northern California. NBC News, "Hammer spark caused largest wildland fire in California history, investigators say," 7 June 2019 But that community is in an area prone to deadly wildfires. San Diego Union-Tribune, "Column: Julian station rebellion unresolved as fire season begins," 5 June 2019 About $7 billion in claims are from the Camp Fire that destroyed the Northern California city of Paradise and killed at least 86 people, making it the deadliest U.S. wildfire in at least a century. Kathleen Ronayne, The Seattle Times, "Insurance claims at $9 billion from California fires," 12 Dec. 2018 The New York Times reports that the largest one—the Camp Fire in Paradise, Calif., located in Butte County in Northern California—has become the deadliest and most destructive wildfire in the state’s history. Carolyn L. Todd, SELF, "The Dangerous Health Risks That Could Follow the California Wildfires," 16 Nov. 2018 Yet the human toll has been even more stunning: At least 56 people have died in the flames (with over 200 still unaccounted for), making it the single deadliest wildfire in state history. Eliza Barclay, Vox, "Photos: what California’s lethal wildfires look like on the ground," 15 Nov. 2018 Attribution research has been crucial in recent years as local leaders have had to grapple with some of the country’s deadliest and most destructive wildfires, floods, and hurricanes. Alissa Walker, Curbed, "Hurricane Florence will dump up to 50 percent more rainfall due to climate change," 13 Sep. 2018

Recent Examples on the Web: Adverb

Other cases detail how similar callousness or poor judgment can turn deadly: In Knox County, Tennessee, an inmate who tried to kill himself with a razor six months earlier was given another one when readmitted on theft charges. Sharon Cohen, The Denver Post, "AP Investigation: Many U.S. jails fail to stop inmate suicides," 18 June 2019 Demonstrations on the Gaza-Israel border have picked up in the past two weeks, sometimes turning deadly as protesters have clashed with Israel’s security forces. Dov Lieber, WSJ, "Six Palestinians Die in Clashes at Gaza-Israel Border," 28 Sep. 2018 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

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.

See More

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

Keep scrolling for more

Learn More about deadly

Statistics for deadly

Last Updated

23 Jun 2019

Look-up Popularity

Time Traveler for deadly

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

See more words from the same century

Keep scrolling for more

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

Keep scrolling for more

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.

Keep scrolling for more

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

What made you want to look up deadly? Please tell us where you read or heard it (including the quote, if possible).

WORD OF THE DAY

having a desire to acquire more things

Get Word of the Day daily email!

Test Your Vocabulary

Words for Summer: A Quiz

  • a closeup of a sunflower
  • Which of the following words means “of or relating to summer”?
True or False

Test your knowledge - and maybe learn something along the way.

TAKE THE QUIZ
Citation

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!