viper

American  

[vahy-per] / ˈvaɪ pər /

noun

• vipers
  plural

1. any of several venomous Old World snakes of the genus Vipera, especially V. berus, a small snake common in northern Eurasia.

2. any related snakes belonging to the family Viperidae, characterized by erectile, venom-conducting fangs.

3. pit viper.

4. any of various venomous or supposedly venomous snakes.

5. a malignant or spiteful person.

6. a false or treacherous person.

7. Military. Viper, a 9-pound (4-kilogram), shoulder-launched, unguided U.S. Army antitank rocket with an effective range of 273 yards (250 meters).

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idioms

1. to nourish a viper in one's bosom, to befriend a person who proves to be treacherous.

viper British  

/ ˈvaɪpə /

noun

1. any venomous Old World snake of the family Viperidae, esp any of the genus Vipera (the adder and related forms), having hollow fangs in the upper jaw that are used to inject venom

2. any of various other snakes, such as the horned viper

3. See pit viper

4. a malicious or treacherous person

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Other Word Forms

Derived Forms

• viper-like
  adjective
• viperish
  adjective
• viperishly
  adverb

Inflected Forms

Nouns

• vipers
  plural

Etymology

Origin of viper

First recorded in 1520–30; from Latin vīpera, variant of unattested vīvipera, noun use of feminine of unattested vīviper, later (as re-formation) vīviparus “bringing forth live young”; see vivi-, -parous

Explanation

A viper is a certain type of poisonous snake. The most common vipers in the United States are rattlesnakes and water moccasins. Vipers are found in most places on earth and they're a diverse group with over 200 species. Vipers have specialized pits on their faces that can detect heat that's emitted from their prey, which gives them a big advantage to sense and catch their prey quickly. Viper is a scientific name for a particular family of snakes that poison others by biting them with hollow fangs that inject venom. And because of that, viper (and snake) are often used to describe spiteful, disloyal, or back-stabbing people.

Example Sentences

See Examples For:

viper vipers

Only when they reviewed the images did the Grammatico twins realise they had captured a mosquito resting on the head of a fer-de-lance viper.

From BBC ● Aug. 25, 2026

Powell compared China’s naval strategy around Taiwan to that of a boa constrictor, moving slowly to overpower its rival, rather than striking dramatically as a viper might.

From The Wall Street Journal ● Jun. 24, 2026

He played Tedros, a wannabe music industry impresario who also happened to be a pseudo-cult-leading viper attracted to the shiny fame of Lily-Rose Depp’s pop star, Jocelyn.

From Salon ● May 19, 2025

Was it a deadly viper or a harmless python?

From Science Magazine ● Mar. 8, 2024

It moved like a young viper: purposeful, silent, and lethal.

From "Messenger" by Lois Lowry

Bouncing down dusty roads, performing at snake-handling parties, rescuing homeowners from vipers and thousands of creatures from nameless obscurity, the snake men appeal to the renegade in us all.

From The Wall Street Journal ● Aug. 28, 2026

In June, Mumbai customs intercepted two passengers arriving from Thailand with dozens of venomous vipers and more than 100 other creatures, including lizards, sunbirds and tree-climbing possums, also arriving from Thailand.

From Barron's ● Oct. 31, 2025

Confronting her audience, she scolded: "I'll tell you something about my good name / It's mine alone to disgrace / I don't cater to all these vipers dressed in empath's clothing."

From BBC ● Aug. 27, 2025

It is visible to pit vipers as heat, giving them a Predator-like advantage for hunting.

From Salon ● Nov. 16, 2024

The vipers were coiled upon themselves, suspended in dingy liquid.

From "Genuine Fraud" by E. Lockhart

Related Words

• cobra