Virulent
Virulent , adjective
[Latin virulentus, from virus poison: compare French virulent. See Virus.]
1.
Extremely poisonous or venomous; very active in doing injury.
A contagious disorder rendered more virulent by uncleanness.
2.
Very bitter in enmity; actuated by a desire to injure; malignant; as, a virulent invective.