‘Sporadic' is an adjective.
Meaning: happening only occasionally or at intervals that are irregular. The events are not periodic.
1. Many Indians have been attacked in the last two years in sporadic outbursts of violence in Australia.
2. The sporadic floods in the region needs pre planned measures to protect the inhabitants.
3. The capital is a very sensitive region. There are cases of sporadic riots in some of its localities.
4. Cholera is common in under developed nations. The sporadic outburst of this disease is a matter of great concern.