Virulence; Virulency

Part of speech: noun (n.)

1. The quality or state of being virulent or venomous; poisonousness; malignancy.

2. Extreme bitterness or malignity of disposition. "Refuted without satirical virulency." Barrow. The virulence of one declaimer, or the profundities and sublimities of the other. I. Taylor.