viper

noun

vi·​per ˈvī-pər 

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

Synonyms

• serpent
• snake

Examples of viper in a Sentence

a viper sliding silently through the field

Recent Examples on the Web

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

But the bulbous embellishment at the end of this viper’s tail is not a tumor or other growth imperfection, but rather one of nature’s trickiest anatomical lures. —Ryley Graham, Smithsonian Magazine, 29 Jan. 2025

Inside, stacks of clear containers hold dozens of cobras, mambas, puff adders and other vipers, including one with tiny horns on its head. —Brian Otieno, New York Times, 6 Jan. 2025

And for vipers, a 2013 study suggests the intense coloration can help the snakes regulate their temperature. —Eli Wizevich, Smithsonian Magazine, 19 Dec. 2024

Word History

Etymology

Middle English vipere, from Latin vipera

First Known Use

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

Phrases Containing viper

• horned viper
• pit viper
• viper's bugloss

Rhymes for viper

• diaper
• hyper
• piper
• riper
• sniper
• wiper
• sandpiper

Kids 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

: pit viper

3

: a venomous or reputedly venomous snake