Vir"u*lent (?), a. [L. virulentus, fr. virus poison: cf. F. virulent. See Virus.]
1.
Extremely poisonous or venomous; very active in doing injury.
A contagious disorder rendered more virulent by uncleanness.
Sir W. Scott.
2.
Very bitter in enmity; actuated by a desire to injure; malignant; as, a virulent invective.
© Webster 1913.