killer

1 of 2

noun

kill·​er ˈki-lər 

1

: one that kills

2

: killer whale

3

a

: one that has a forceful, violent, or striking impact

b

: one that is extremely difficult to deal with

killer

2 of 2

adjective

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 of killer

Noun

• headache
• job

Adjective

• lethal
• deadly
• fatal

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

Noun

Her large flat-screen living room television was missing, leading detectives at the time to surmise the killer may have known that footage from the victim’s surveillance cameras could be watched on that TV. — Fort Worth Star-Telegram, 1 Aug. 2026

Crystal Lake stars Emmy Award nominee Linda Cardellini (Dead to Me, Mad Man) as Pamela Voorhees, the mother of the notorious Friday the 13th killer Jason. — Scott Roxborough, HollywoodReporter, 31 July 2026

Eager as the women are to nab a serial killer, going after the network’s Epstein-like billionaire ringleader proves even more tempting. — Inkoo Kang, New Yorker, 30 July 2026

Could Kohberger have been a serial killer in the making, a man who hates women, or is there enough evidence to exonerate him altogether? — Britt Hayes, Entertainment Weekly, 30 July 2026

Word History

First Known Use

Noun

15th century, in the meaning defined at sense 1

Adjective

1939, in the meaning defined at sense 2

Phrases Containing killer

• killer app
• killer bee
• killer cell
• killer instinct
• killer T cell
• killer T lymphocyte
• killer whale
• lady-killer
• natural killer cell
• pain-killer
• time killer

Rhymes for killer

• biller
• chiller
• driller
• filler
• hilar
• hiller
• pillar
• quiller
• siller
• spiller
• stiller
• thriller

Kids Definition

killer

1 of 2 noun

ˈkil-ər

1

: one that kills

2

: killer whale

killer

2 of 2 adjective

1

: strikingly impressive or effective

a killer smile

2

: extremely difficult

a killer exam

also : causing death or devastation

a killer tornado