adjective

virulent

VEER-uh-luhnt/ˈvɪrələnt/

Capable of causing severe harm.

A virulent strain of the virus spreads through the town.

A severe infectious outbreak: two visibly debilitated patients with the same conspicuous rash require oxygen while a fully protected clinician attends them.

Etymology

The image is being full of poison, first applied in English to wounds and ulcers containing poisonous or corrupt matter. This developed into extreme malignancy in disease and, figuratively, bitter or spiteful hostility.

In context

Scary Interesting8:51

it's one of the most virulent pathogens known to science, capable of killing up to 88% of those it infects.

The Deadliest Cave on Earth

More examples

The virulent infection requires immediate treatment.
This strain is more virulent than the one detected last year.
She faces virulent attacks from opponents of her proposal.

Forms

virulent · more virulent · most virulent

virulence noun — The capacity to cause severe harm.

virulently adverb — In an intensely harmful or hostile manner.

Similar words

harmful: Broader term that does not imply extreme severity.
toxic: Usually suggests poisoning rather than severe infection or hostility.
vicious: Emphasizes cruelty or aggression rather than disease-causing power.