Main Entry: vi·per

Pronunciation: \ˈvī-pər\

Function: noun

Etymology: Middle English vipere, from Latin vipera

Date: 15th century

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