Disquiet (noun)

A feeling of mild anxiety or unease.

Origin:

Middle english (also in the sense 'disrupt, disturb'): from old french desquiet, from des- (expressing negation) + quiet 'quiet, calm'.

Examples:

1. She felt a disquiet in her stomach as she waited for the test results.
2. There was a sense of disquiet among the passengers as the plane began to shake.
3. The sudden silence filled the room with disquiet.
4. His sudden disappearance caused much disquiet among his friends and family.
5. The disquiet in the market was causing a drop in the stock prices.