KILLER Synonyms: 201 Similar and Opposite Words

killer 1 of 2

noun

ˈki-lər

Definition of killer

as in headache

a dull, unpleasant, or difficult piece of work weeding out that overgrown garden is going to be a killer

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Antonyms & Near Antonyms

as in murderer

a person who kills another person gunned down by hired killers

Synonyms & Similar Words

killer

2 of 2

adjective

as in lethal

likely to cause or capable of causing death killer viruses that claimed millions of lives

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as in difficult

requiring considerable physical or mental effort a killer exercise program guaranteed to whip you into shape

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Example Sentences

Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.

Recent Examples of killer

Noun

Some weeks the flashbacks are momentum-killers, interrupting the intense drama in Silo 18. — Noel Murray, Vulture, 21 Aug. 2026 Most commercial mold killers can be used to clean a washer seal. — Mary Marlowe Leverette, Southern Living, 20 Aug. 2026 Following the second round of deaths, Alfred and Thomas realize that the killer is specifically targeting the police. — Aramide Tinubu, Variety, 20 Aug. 2026 While a knockout voice is one way to capture an audience’s attention, a splash of sequins and a killer stiletto helped stick the landing. — Bianca Betancourt, CNN Money, 20 Aug. 2026 See All Example Sentences for killer

Recent Examples of Synonyms for killer

Noun

These include a severe or persistent headache, changes in vision such as blurred vision or seeing spots, pain in the upper abdomen, significant swelling of the face or hands, shortness of breath, and nausea or vomiting later in pregnancy.

— Faye Chiu, CNN Money, 21 Aug. 2026
But in some cases, West Nile can reach the brain and cause extreme headaches, meningitis, tremors, convulsions and paralysis.

— Mary Randolph, Scientific American, 21 Aug. 2026

Definition of headache

Noun

Triple-murderer Erin Patterson appealed her convictions Wednesday for poisoning four of her estranged husband’s relatives with death cap mushrooms.

— ABC News, ABC News, 18 Aug. 2026
If the murderer was at the door, the truth must nonetheless be told, whatever the consequences.

— Adam Gopnik, New Yorker, 17 Aug. 2026

Definition of murderer

Adjective

Though the year-plus-long story line also involved a replacement Batman proving far too lethal to be let loose on Gotham for long, and the original Batman going on a soul-searching quest, what most remember is Bane and Batman’s poor, poor spine.

— Daniel Dockery, Vulture, 24 Aug. 2026
No, that's – the MMR vaccine is not a lethal vaccine, and it is offered in other countries, the measles, in particular, separately, like in Japan.

— CBS News, CBS News, 23 Aug. 2026

Definition of lethal

Adjective

The California Board of Pharmacy in 2025 reversed course on regulations that would have made the supplement more difficult to acquire after pushback from some firefighters.

— ABC News, ABC News, 23 Aug. 2026
Striking out on her own was a difficult transition, but embracing her solitude gave her the space to learn more about herself and make her own personal decisions, such as getting her cat or making meals of her choosing.

— Amen Galinato, CNN Money, 23 Aug. 2026

Definition of difficult

Noun

Denver is facing a $200 million budget deficit in 2026 and has laid off 169 city workers, cut city services and left hundreds of city jobs unfilled because of the budget squeeze.

— Brian Maass, CBS News, 21 Aug. 2026
The court dismissed the case against her manager, who also lost his job.

— Simone McCarthy, CNN Money, 21 Aug. 2026

Definition of job

Noun

The would-be assassin was arrested by police and led investigators to two members of a Russian mob network who had enlisted him on behalf of Iran.

— Cora Engelbrecht, New Yorker, 24 Aug. 2026
Bannerman centers on the eponymous Paul Bannerman, a lethal covert operative who convinces a group of the world’s most deadly assassins to quit the spy game for a chance to lead normal lives in the suburbs of Connecticut.

— Nellie Andreeva, Deadline, 20 Aug. 2026

Definition of assassin

Adjective

Rabies is a deadly virus that spreads to people from the saliva of infected animals, according to the Mayo Clinic.

— Nicholas Lentz, CBS News, 24 Aug. 2026
Tropical Storm Moke is making its closest approach to Hawaii as the state braces for its second tropical threat in less than a week after deadly Hurricane Lala tore through parts of the islands.

— Tyler Ory, CNN Money, 23 Aug. 2026

Definition of deadly

Adjective

Sharing her new life on social media helped give Hoadley a sense of empowerment despite her challenging circumstances.

— Amen Galinato, CNN Money, 23 Aug. 2026
The Heart Is a Lonely Hunter Carson McCullers’ remarkable debut novel tells a story of the American South, one set in Georgia and peopled with a cast of characters that exist in a rich, layered, and challenging reality.

— Caroline Rogers, Southern Living, 22 Aug. 2026