n. 1 any venomous snake of the family Viperidae, esp. the common viper (see ADDER). 2 a malignant or treacherous person. viper in one's bosom a person who betrays those who have helped him or her. viper's bugloss a stiff bristly blue-flowered plant, Echium vulgare. viper's grass scorzonera. viperine adj. viperish adj. viper-like adj. viperous adj.
[ F vipère or L vipera f. vivus alive + parere bring forth ]