any venomous Old World snake of the family Viperidae, esp any of the genus Vipera (the adder and related forms), having hollow fangs in the upper jaw that are used to inject venom
2.
any of various other snakes, such as the horned viper
3. pit viper
4.
a malicious or treacherous person
Derived forms
viper-like (ˈviper-ˌlike)
adjective
Word origin
C16: from Latin vīpera, perhaps from vīvus living + parere to bear, referring to a tradition that the viper was viviparous