VI'PEROUS, adjective [Latin viperus.] Having the qualities of a viper; malignant; venomous; as a viperous tongue. VIPER'S BUGLOSS, noun A plant of the genus Echium. VIPER'S GRASS, noun A plant of the genus Scorzonera.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI