A venomous snake, most likely a viper or adder, named perhaps for its hissing sound. Isaiah uses the term in prophecies of judgment and danger, depicting viper eggs and the deadly nature of wickedness. Job employs it in Bildad's warning that the wicked person will 'suck the poison of vipers' and be killed by the viper's tongue. The serpent embodies lethal danger lurking in seemingly safe places, a natural metaphor for sin's deceptive and deadly nature.