Worrywart (noun)

A person who worries excessively and unnecessarily.

Origin:

Derived from the combination of the words "worry" and "wart" which means a small, hard, benign growth on the skin.

Examples:

1. He was a worrywart who fretted about every little thing.
2. She was a worrywart who always imagined the worst.
3. The worrywart was constantly anxious about her children.
4. He was a classic worrywart who could never relax.
5. She was a worrywart who was always fretting about something.