Virulent \Vir"u*lent\, a. [L. virulentus, fr. virus poison: cf. F. virulent. See Virus.]

1. Extremely poisonous or venomous; very active in doing injury. [1913 Webster]

A contagious disorder rendered more virulent by uncleanness. --Sir W. Scott. [1913 Webster]

2. Very bitter in enmity; actuated by a desire to injure; malignant; as, a virulent invective. [1913 Webster]

Source: The Collaborative International Dictionary of English v.0.48
 

149 Moby Thesaurus words for "virulent": acerb, acerbate, acerbic, acid, acidic, acidulent, acidulous, acrid, acrimonious, acute, antagonistic, antipathetic, astringent, baleful, baneful, belligerent, biting, bitter, brutal, burning, catching, caustic, choleric, clashing, colliding, communicable, conflicting, contagious, corroding, corrosive, corrupting, corruptive, counterproductive, cutting, damaging, dangerous, deadly, death-bringing, deathful, deathly, deleterious, despiteful, destructive, detrimental, disadvantageous, disserviceable, distressing, double-edged, drastic, edged, embittered, envenomed, escharotic, excessive, exorbitant, extravagant, extreme, fatal, feral, fierce, full of hate, furious, great, harmful, harsh, hateful, hostile, hurtful, immoderate, incisive, infectious, infective, injurious, intemperate, intense, internecine, keen, killing, lethal, malefic, malevolent, malicious, malign, malignant, mephitic, miasmal, miasmatic, miasmic, mischievous, mordacious, mordant, mortal, nasty, noisome, noxious, ominous, outrageous, penetrating, pernicious, pestiferous, pestilential, piercing, poignant, poison, poisonous, prejudicial, quarrelsome, rancorous, rankled, repugnant, resentful, resenting, rigorous, rough, sarcastic, savage, scatheful, scathing, septic, set against, severe, sharp, sore, spiteful, splenetic, splitting, stabbing, stewing, stinging, strident, stringent, tart, tough, toxic, toxicant, toxiferous, trenchant, unconscionable, unfriendly, unhealthy, unwholesome, vehement, venenate, veneniferous, venenous, venomous, vicious, violent, vitriolic

Source: Moby Thesaurus II by Grady Ward, 1.0
 

virulent adj
1: extremely poisonous or injurious; producing venom; "venomous snakes"; "a virulent insect bite" [syn: deadly, venomous]
2: infectious; having the ability to cause disease [ant: avirulent]
3: harsh or corrosive in tone; "an acerbic tone piercing otherwise flowery prose"; "a barrage of acid comments"; "her acrid remarks make her many enemies"; "bitter words"; "blistering criticism"; "caustic jokes about political assassination, talk-show hosts and medical ethics"; "a sulfurous denunciation" [syn: acerb, acerbic, acid, acrid, bitter, blistering, caustic, sulfurous, sulphurous, venomous, vitriolic]

Source: WordNet (r) 2.0
 

Virulent \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.

Source: Webster's Revised Unabridged Dictionary (1913)