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

A Gaboon viper — a highly venomous snake native to the rainforests and savannas of sub-Saharan Africa — was on the loose in a Santa Ana neighborhood.

From Los Angeles Times ● Oct. 1, 2026

The sighting of the extremely venomous viper, which has the longest fangs of any snake in the world, spurred the Santa Ana Police Department to issue a public advisory accompanied by exclamation points.

From Los Angeles Times ● Sep. 29, 2026

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

‘That will stop the poisnowse juices from the venomsome viper going up your leg and into your heart!’

From "The BFG" by Roald Dahl

Gaboon vipers live on the ground and can weigh more than 45 pounds — too heavy to be adequately supported by a thin tree branch.

From Los Angeles Times ● Oct. 1, 2026

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 their post, they said they had seized three spider-tailed horned vipers, five Asian leaf turtles and 44 Indonesian pit vipers from the passenger.

From BBC ● Jun. 2, 2025

While 95Mat5 is effective against the venom of all elapids, it does not block the venom of vipers -- the second group of venomous snakes.

From Science Daily ● Feb. 21, 2024

Somewhat recovered, Otto took to the branches while I scrambled through the overgrowth, making sure to shuffle my feet so I wouldn’t step on any wasp nests or vipers or millipedes.

From "Endangered" by Eliot Schrefer

Related Words

• cobra