[vir-yuh-luhnt, vir-uh-]
  1. actively poisonous; intensely noxious: a virulent insect bite.
  2. Medicine/Medical. highly infective; malignant or deadly.
  3. Bacteriology. causing clinical symptoms.
  4. violently or spitefully hostile.
  5. intensely bitter, spiteful, or malicious: a virulent attack.

Origin of virulent

1350–1400; Middle English verulent < Latin vīrulentus, equivalent to vīr(us) poison (see virus) + -ulentus -ulent
Related formsvir·u·lent·ly, adverbhy·per·vir·u·lent, adjectivehy·per·vir·u·lent·ly, adverbnon·vir·u·lent, adjectivenon·vir·u·lent·ly, adverbsu·per·vir·u·lent, adjectivesu·per·vir·u·lent·ly, adverbun·vir·u·lent, adjectiveun·vir·u·lent·ly, adverb
Can be confusedviolent virulent

Synonyms for virulent

Antonyms for virulent Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for non-virulent

Historical Examples of non-virulent

British Dictionary definitions for non-virulent


    1. (of a microorganism) extremely infective
    2. (of a disease) having a rapid course and violent effect
  1. extremely poisonous, injurious, etc
  2. extremely bitter, hostile, etc
Derived Formsvirulently, adverb

Word Origin for virulent

C14: from Latin vīrulentus full of poison, from vīrus poison; see virus
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for non-virulent



c.1400, in reference to wounds, ulcers, etc., "full of corrupt or poisonous matter," from Latin virulentus "poisonous," from virus "poison" (see virus). Figurative sense of "violent, spiteful" is attested from c.1600. Related: Virulently.

Online Etymology Dictionary, © 2010 Douglas Harper

non-virulent in Medicine


[vîryə-lənt, vîrə-]
  1. Extremely infectious, malignant, or poisonous. Used of a disease or toxin.
  2. Capable of causing disease by breaking down protective mechanisms of the host. Used of a pathogen.
  3. Intensely irritating, obnoxious, or harsh.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.