*viper*

n. [ F. vipère, L. vipera, probably contr. fr. vivipera; vivus alive + parere to bring forth, because it was believed to be the only serpent that brings forth living young. Cf. Quick, a., Parent, Viviparous, Wivern, Weever. ] [ 1913 Webster ]

1. (Zool.) Any one of numerous species of Old World venomous snakes belonging to Vipera, Clotho, Daboia, and other genera of the family Viperidae. [ 1913 Webster ]

There came a viper out of the heat, and fastened on his hand. Acts xxviii. 3. [ 1913 Webster ]

☞ Among the best-known species are the European adder (Pelias berus), the European asp (Vipera aspis), the African horned viper (Vipera cerastes), and the Indian viper (Daboia Russellii). [ 1913 Webster ]

2. A dangerous, treacherous, or malignant person. [ 1913 Webster ]

Who committed
To such a viper his most sacred trust
Of secrecy. Milton. [ 1913 Webster ]

3. Loosely, any venomous or presumed venomous snake. [ PJC ]

Horned viper. (Zool.) See Cerastes. --
Red viper (Zool.), the copperhead. --
Viper fish (Zool.), a small, slender, phosphorescent deep-sea fish (Chauliodus Sloanii). It has long ventral and dorsal fins, a large mouth, and very long, sharp teeth. --
Viper's bugloss (Bot.), a rough-leaved biennial herb (Echium vulgare) having showy purplish blue flowers. It is sometimes cultivated, but has become a pestilent weed in fields from New York to Virginia. Also called blue weed. --
Viper's grass (Bot.), a perennial composite herb (Scorzonera Hispanica) with narrow, entire leaves, and solitary heads of yellow flowers. The long, white, carrot-shaped roots are used for food in Spain and some other countries. Called also viper grass. [ 1913 Webster ]