proliferate
/pɹəˈlɪf.əɹ.eɪt/verb
To grow or spread quickly in number.
Example sentences
- “Coffee shops have proliferated in this neighborhood over the past year.”
- “Fake news stories proliferate quickly on social media.”
Formal; the subject is usually something multiplying beyond control, like weapons or rumors. 'Nuclear proliferation' is the famous noun use.