Noah Webster
Virulence
VIR'ULENCE, noun [from virulent.]
1. That renders it extremely active in doing injury; acrimony; malignancy; as the virulence of poison.
2. Acrimony of temper; extreme bitterness or malignity; as the virulence of enmity or malice; the virulence of satire; to attack a man with virulence