The noun form of worry is worry itself.
It refers to the state or feeling of being anxious or concerned about something.
Examples:
- “She felt a lot of worry before the exam.”
- “His constant worry about the future is affecting his health.”
Other related noun forms include:
- Worrier: A person who worries a lot.
- Worriment: A less common word for the state of worry or anxiety.
But the most common noun form is simply worry.