perturbation

noun

1. 1

   the act of causing disorder

2. 2

   a disposition that is confused or nervous and upset

3. 3

   activity that is a malfunction, intrusion, or interruption

   the term `distress' connotes some degree of perturbation and emotional upset

   he looked around for the source of the disturbance

4. 4

   (physics) a secondary influence on a system that causes it to deviate slightly

5. 5

   an unhappy and worried mental state

   there was too much anger and disturbance

   she didn't realize the upset she caused me