Thunderbolt (noun)

1. A flash of lightning accompanied by thunder.
2. Something sudden, violent, and unexpected.

Origin:

Middle english: from old english thunorboltt, from thunor "thunder" + boltt "bolt".

Examples:

1. The sky was lit up by a thunderbolt during the storm.
2. The thunderbolt struck the tree and split it in half.
3. The news of his death was a thunderbolt to the family.
4. His proposal was a thunderbolt, she never expected it.
5. The company's sudden bankruptcy was a thunderbolt to the industry.