1
: one that kills
2
3
a
: one that has a forceful, violent, or striking impact
b
: one that is extremely difficult to deal with
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
Synonyms
Examples of killer in a Sentence
Noun
Heart disease is the leading killer of both men and women.
The chemical is used as a weed killer.
Adjective
killer viruses that claimed millions of lives
a killer exercise program guaranteed to whip you into shape
Recent Examples on the Web
Sandee Lamotte, CNN, 18 June 2024
Deb, first a police officer and later lieutenant, is the sister of the titular serial killer who moonlights as a blood spatter analyst for the Miami-Dade Metro Police Department.
—Rosy Cordero, Deadline, 17 June 2024
Of these, 83% were caused by hepatitis B and 17% by hepatitis C.
Related: Viral hepatitis is a silent killer.
—Danjuma Adda, STAT, 16 June 2024
Leo Schofield served a horrifying 35 years for the 1987 murder of his wife… despite evidence pointing to another suspect and the detailed confessions of that real killer.
—Staff Author, EW.com, 16 June 2024
See all Example Sentences for killer 
Noun
But when neurons die due to injury, age or a disease such as Alzheimer’s, microglia become sidetracked, turning into killers to fend off whatever seems to be damaging the brain, Tanzi said.
—Sandee Lamotte, CNN, 18 June 2024
Deb, first a police officer and later lieutenant, is the sister of the titular serial killer who moonlights as a blood spatter analyst for the Miami-Dade Metro Police Department.
—Rosy Cordero, Deadline, 17 June 2024
Of these, 83% were caused by hepatitis B and 17% by hepatitis C.
Related: Viral hepatitis is a silent killer.
—Danjuma Adda, STAT, 16 June 2024
Leo Schofield served a horrifying 35 years for the 1987 murder of his wife… despite evidence pointing to another suspect and the detailed confessions of that real killer.
—Staff Author, EW.com, 16 June 2024
See all Example Sentences for killer
These examples are programmatically compiled from various online sources to illustrate current usage of the word 'killer.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.
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Cite this Entry
“Killer.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/killer. Accessed 2 Jul. 2024.
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