noun

1. any of a widespread family (Viperidae) of venomous snakes, including the pit vipers, the European adder, and the African puff adder; solenoglyph
2. any of various other poisonous or supposedly poisonous snakes
3. 1. a malicious or spiteful person
   2. a treacherous person

Etymology: OFr < L vipera, contr. < ? *vivipara, producing live young < vivus, living (see bio-) + parere, to bear: see -parous: from the notion that the viper does not lay eggs