Virulent (adjective)

1. Very poisonous or toxic.
2. Intensely harmful, malicious, or hostile.
3. Of a disease-causing agent (such as a bacterium), highly infectious and pathogenic.

Origin:

Derived from the latin word virulentus, meaning poisonous or dangerous.

Examples:

1. The virulent strain of the virus spread rapidly and had a high mortality rate.
2. Her virulent criticism of the government's policies was echoed by many in the opposition.
3. The virulent bacteria caused a severe outbreak of food poisoning, leading to the recall of hundreds of food products.
4. The virulent ideology of the extremist group had led to numerous acts of terrorism.
5. The virulent poison killed the animal within minutes of ingesting it.