noun

1. An eruption; the sudden appearance of a rash, disease, etc.

   “Any epidemic outbreak causes understandable panic.”

2. An outburst or sudden eruption, especially of violence and mischief.

   “There has been an outbreak of broken windows in the street.”

3. A sudden increase.

   “There has been an outbreak of vandalism at the school.”

Synonyms: outburst, tumult

verb

1. To burst out.

2. To break forth.