1
a
: 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
Examples of viper in a Sentence
a viper sliding silently through the field
Recent Examples on the Web
According to a study published April 23 in the journal Evolution, some vipers are producing venoms containing fewer and more focused toxins, despite living in extremely varied environments.
—
Andrew Paul, Popular Science, 23 Apr. 2025
Maybe not coincidentally, the nicest guy in the vipers’ nest is the producer played by Joseph Cotton.
—Thomas Doherty, HollywoodReporter, 20 Apr. 2025
Their relationship is enviable to the vipers around them, until Kathryn’s name appears on Philip’s list.
—Angelica Jade Bastién, Vulture, 14 Mar. 2025
The 2024 photo, however, clearly showed a Vipera berus, also known as the common European adder or common European viper, on Sylt Island, the study said.
—Aspen Pflughoeft, Miami Herald, 21 Mar. 2025
See All Example Sentences for viper
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Andrew Paul, Popular Science, 23 Apr. 2025
Maybe not coincidentally, the nicest guy in the vipers’ nest is the producer played by Joseph Cotton.
—Thomas Doherty, HollywoodReporter, 20 Apr. 2025
Their relationship is enviable to the vipers around them, until Kathryn’s name appears on Philip’s list.
—Angelica Jade Bastién, Vulture, 14 Mar. 2025
The 2024 photo, however, clearly showed a Vipera berus, also known as the common European adder or common European viper, on Sylt Island, the study said.
—Aspen Pflughoeft, Miami Herald, 21 Mar. 2025
See All Example Sentences for viper
Cite this Entry
“Viper.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/viper. Accessed 17 May. 2025.
Copy CitationKids Definition
viper
noun
vi·per
ˈvī-pər 
1
: any of a family of poisonous snakes having heavy bodies, broad heads, and hollow tube-shaped fangs and including Old World snakes and the pit vipers
2
: any snake that is poisonous or that is believed to be poisonous
Medical Definition
viper
noun
vi·per
ˈvī-pər
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
3
: a venomous or reputedly venomous snake
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