perturbation
noun
[ ˌpəːtəˈbeɪʃ(ə)n ]
• anxiety; mental uneasiness.
• "she sensed her friend's perturbation"
• a deviation of a system, moving object, or process from its regular or normal state or path, caused by an outside influence.
• "these shifts and swings in wildlife populations are possibly related to climatic perturbations"
Origin:
late Middle English: from Latin perturbatio(n- ), from the verb perturbare ‘disturb greatly’ (see perturb).
