kill·​er | \ ˈki-lər \

Definition of killer

 (Entry 1 of 2)

1 : one that kills
3a : one that has a forceful, violent, or striking impact
b : one that is extremely difficult to deal with



Definition of killer (Entry 2 of 2)

1 : strikingly impressive or effective a killer smile a killer résumé
2 : extremely difficult to deal with a killer fastball also : causing death or devastation a killer tornado

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Synonyms & Antonyms for killer

Synonyms: Noun

bear, beast, chore, headache, job, labor

Synonyms: Adjective

baleful, deadly, deathly, fatal, fell, lethal, mortal, murderous, pestilent, terminal, vital

Antonyms: Adjective

healthful, healthy, nonfatal, nonlethal, wholesome

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Examples of killer in a Sentence


Heart disease is the leading killer of both men and women. The chemical is used as a weed killer.


killer viruses that claimed millions of lives a killer exercise program guaranteed to whip you into shape
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Recent Examples on the Web: Noun

The category killer is being able to charge half the price [of the going rate]. Barbara Peterson, Condé Nast Traveler, "JetBlue Founder David Neeleman on How New Airline Moxy Will Change the Way We Fly," 12 Dec. 2018 The killer was Juan Lopez, reportedly her ex-fiancé. Anna North, Vox, "At Chicago’s Mercy Hospital, domestic violence became multiple homicide. It’s part of a disturbing pattern.," 21 Nov. 2018 The idea sounds well-intentioned: Stop using weed killer and spray vinegar instead. Margaret Roach, Good Housekeeping, "Why It Can Be Dangerous to Use Vinegar to Kill Weeds," 15 Aug. 2018 Matt Dillon stars as a serial killer named Jack, and the film chronicles five of Jack’s most pivotal killings — which involve the gruesome dismemberment of children and a scene that can only be described as misogynistic human taxidermy. Alissa Wilkinson, Vox, "Critics called Lars von Trier’s new movie “repulsive.” It’s being released twice.," 6 Dec. 2018 Potential items include a range of food options, pain killers, and emergency essentials like diapers or an ice scraper. Jon Porter, The Verge, "Alphabet’s Wing is launching a free 10-minute drone delivery service in Finland," 5 Dec. 2018 Carol being a cold-hearted killer isn’t new; going to that place, and then slowly coming back around to Rick’s more moderate point of view, was a major part of her character arc over the life of the series. Bryan Bishop, The Verge, "The Walking Dead’s fresh start looks like a big step back," 12 Nov. 2018 Dylan McDermott, Samantha Mathis, and Charlie Plummer star in this eerie new movie (based on true events) about a son who suspects his father is a serial killer. Christopher Rosa, Glamour, "10 Things Happening in Music, TV, and Movies This Week You Need to Know About," 11 Nov. 2018 Look at that beautiful bay window the killer just crashed through! Taylor Mead, House Beautiful, "Can You Guess How Much These Classic Horror-Film Houses Cost?," 30 Oct. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'killer.' 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 killer


15th century, in the meaning defined at sense 1


1951, in the meaning defined at sense 1

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Dictionary Entries near killer





killer app

killer bar

killer bee

Statistics for killer

Last Updated

13 Jan 2019

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Time Traveler for killer

The first known use of killer was in the 15th century

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More Definitions for killer



English Language Learners Definition of killer

 (Entry 1 of 2)

: a person or thing that kills someone or something

: something that is very difficult



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

: causing death or destruction

: very impressive or appealing

: very difficult


kill·​er | \ ˈki-lər \

Kids Definition of killer

 (Entry 1 of 2)

: someone or something that takes the life of a person or animal



Kids Definition of killer (Entry 2 of 2)

1 : very impressive or effective a killer smile
2 : very difficult a killer exam
3 : causing death or ruin a killer tornado

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More from Merriam-Webster on killer

Rhyming Dictionary: Words that rhyme with killer

Thesaurus: All synonyms and antonyms for killer

Spanish Central: Translation of killer

Nglish: Translation of killer for Spanish Speakers

Britannica English: Translation of killer for Arabic Speakers

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