knife

American  

[nahyf] / naɪf /

noun

plural

knives

1. an instrument for cutting, consisting essentially of a thin, sharp-edged, metal blade fitted with a handle.

2. a knifelike weapon; dagger or short sword.

3. any blade for cutting, as in a tool or machine.

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verb (used with object)

knifed, knifing

1. to apply a knife to; cut, stab, etc., with a knife.

2. to attempt to defeat or undermine in a secret or underhanded way.

verb (used without object)

knifed, knifing

1. to move or cleave through something with or as if with a knife.

   The ship knifed through the heavy seas.

idioms

1. under the knife, in surgery; undergoing a medical operation.

   The patient was under the knife for four hours.

knife British  

/ naɪf /

noun

1. a cutting instrument consisting of a sharp-edged often pointed blade of metal fitted into a handle or onto a machine

2. a similar instrument used as a weapon

3. to have a grudge against or victimize someone

4. to make a bad situation worse in a deliberately malicious way

5. people are determined to harm or put a stop to someone

   the knives are out for Stevens

6. undergoing a surgical operation

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verb

1. to cut, stab, or kill with a knife

2. to betray, injure, or depose in an underhand way

knife More Idioms  

1. see at gunpoint (knifepoint); under the knife; you could cut it with a knife.

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Other Word Forms

• knifelike adjective
• knifer noun

Etymology

Origin of knife

before 1100; Middle English knif, Old English cnīf; cognate with Dutch knijf, German Kneif, Old Norse knīfr

Example Sentences

Nevertheless, investors should watch Bitcoin through the long weekend with the Middle East situation on a knife edge and market-moving news all but inevitable.

From Barron's • Apr. 3, 2026

A scene in which Bill taps his glass eye with a knife was not some special effect.

From The Wall Street Journal • Apr. 1, 2026

When baked, the streusel should form a craggy, golden crust that cracks gently under a knife.

From Salon • Mar. 31, 2026

Supporters have said the success of Glyndŵr National Park was "on a knife edge", with the Senedd election adding further uncertainty.

From BBC • Mar. 26, 2026

“They say,” Khrushchev explained, “that when someone goes bear hunting for the first time, he takes a wooden knife with him—so it is easier to clean his pants.”

From "Fallout: Spies, Superbombs, and the Ultimate Cold War Showdown" by Steve Sheinkin

Related Words

• bayonet
• blade
• cutter
• dagger
• machete
• scalpel
• sickle
• skewer
• sword