definition of
perturbation

[1] #1 perturbation n. [disturbance, upset] an unhappy and worried mental state; "there was too much anger and disturbance"; "she didn't realize the upset she caused me". wn

[2] #2 perturbation n. (physics) a secondary influence on a system that causes it to deviate slightly. wn

[3] #3 perturbation n. [disturbance] 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"; "there was a disturbance of neural function". wn

[4] #4 perturbation n. [fluster] a disposition that is confused or nervous and upset. wn

[5] #5 perturbation n. [disruption] the act of causing disorder. wn