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 of viper

• snake
• serpent

Examples of viper in a Sentence

a viper sliding silently through the field

Recent Examples on the Web

Of the thirty-six snakes tested for striking speed at VenomWorld in Paris, only the blunt-nosed viper lost a fang. —Rosa Lyster, Harpers Magazine, 30 Dec. 2025

Other shipments sent by Lin included alligator lizards, venomous green tree vipers and palm pit vipers, all protected by the Convention on International Trade in Endangered Species of Wild Fauna and Flora. —Marc Ramirez, USA Today, 30 Dec. 2025

Now, young people are buying venomous pet vipers. —Alexandra Banner, CNN Money, 16 Dec. 2025

Kids can build three different toys — an astronaut figure, a futuristic space dog, and a space viper jet with a seat for a minifigure to fly it. —Rachel Trujillo, PEOPLE, 1 Dec. 2025

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 the family Viperidae and especially of an Old World subfamily (Viperinae)

2

: pit viper

3

: a venomous or reputedly venomous snake