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

• snake
• serpent

Examples of viper in a Sentence

a viper sliding silently through the field

Recent Examples on the Web

How to identify venomous snakes in Texas Texas is home to four venomous snakes, three of which belong to the same family — the pit vipers. —Brandi D. Addison, Austin American Statesman, 31 July 2025

These creatures included a spider, a snail, dog, bull, maggot, cockroach, two kinds of snake (a viper and a grass snake), and ants. —Jack Beresford, MSNBC Newsweek, 28 July 2025

With a swift flick, the rope shoots forward, wrapping around the dummy’s horns like a viper striking its prey. —Kansas City Star, 23 July 2025

But Cate Blanchett in her couture-worthy ensembles as Cinderella’s stepmother, Lady Tremaine, steals the picture with her biting dialogue and viper’s smile. —Staff Author, EW.com, 22 Mar. 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 an Old World subfamily (Viperinae) of the family Viperidae

2

: pit viper

3

: a venomous or reputedly venomous snake