vi·​per | \ ˈvī-pər How to pronounce viper (audio) \

Definition of viper

1a : a common Eurasian venomous snake (Vipera berus) that attains a length of about two feet (0.6 meter), varies in color from red, brown, or gray with dark markings to black, and is usually not fatal to humans broadly : any of a family (Viperidae) of venomous snakes that includes Old World snakes (subfamily Viperinae) and the pit vipers
b : a venomous or reputedly venomous snake
2 : a vicious or treacherous person

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Synonyms for viper


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Examples of viper in a Sentence

a viper sliding silently through the field
Recent Examples on the Web There is no antivenom for the African bush viper, and bites can cause fevers or internal bleeding, which can be fatal. Wilson Wong, NBC News, "Venomous viper bites worker at San Diego Zoo," 13 Apr. 2021 The snake involved is an African bush viper, also known as Atheris squamigera. Winston Gieseke, USA TODAY, "In California: Newsom talks tough on reopening public schools; more details in Smart case," 15 Apr. 2021 The eastern box turtle is native to forested regions of the East Coast and Midwest, and the Gaboon viper is native to central sub-Saharan Africa. Jeremy Beaman, Washington Examiner, "South Carolina man arrested on federal charges after trafficking snakes and turtles," 6 Apr. 2021 There's something about Michigan's viper linebackers and playing Minnesota. Orion Sang, Detroit Free Press, "Michigan football dominating Minnesota with big plays: 1st-half observations," 25 Oct. 2020 But the sidewinding rattlesnake, which comes from a different branch of the viper family tree, still has a few vestigial belly spikes as well as pits. New York Times, "The Skin-Deep Physics of Sidewinder Snakes," 1 Feb. 2021 In contrast, the Saharan sand viper had only tiny uniform pits across its belly, reports Cosmos. Elizabeth Gamillo, Smithsonian Magazine, "Snakeskin Reveals Secrets Behind a Sidewinder’s Twisted Wiggle," 8 Feb. 2021 The extremely venomous mountain fer-de-lance viper has large fangs and heat-sensing pits on its head to help detect prey. Aaliyah Harris, CNN, "20 new species found, and lost wildlife rediscovered, in the Bolivian Andes," 13 Dec. 2020 And in general, most venomous viper snakes have tens to hundreds of toxic proteins. Kate Baggaley, Popular Science, "Rattlesnake venom is lethal, but understanding it could save lives," 25 Jan. 2021

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'viper.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of viper

15th century, in the meaning defined at sense 1a

History and Etymology for viper

Middle English vipere, from Latin vipera

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Time Traveler for viper

Time Traveler

The first known use of viper was in the 15th century

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Last Updated

29 Apr 2021

Cite this Entry

“Viper.” Dictionary, Merriam-Webster, Accessed 7 May. 2021.

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English Language Learners Definition of viper

: a type of poisonous snake


vi·​per | \ ˈvī-pər How to pronounce viper (audio) \

Kids Definition of viper

: a poisonous heavy-bodied snake with long hollow fangs


vi·​per | \ ˈvī-pər How to pronounce viper (audio) \

Medical Definition of viper

1 : a common Eurasian venomous snake of the genus Vipera (V. berus) that attains a length of about two feet (0.6 meter), varies in color from red, brown, or gray with dark markings to black, and whose bite is usually not fatal to humans broadly : any snake of an Old World subfamily (Viperinae) of the family Viperidae
2 : pit viper
3 : a venomous or reputedly venomous snake

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